text:
Is tongue rolling genetic?
Is the ability to roll your tongue or not truly inherited or genetic? What I have gathered from school has been contradicting with evidence I found elsewhere.

I could only find fairly old literature on the subject, so take this with caution.
Some papers seem to indicate some sort of genetic component to tongue rolling, although the precise molecular basis are not really described (but, again, these are 30-40 years old papers...)
From: Inheritance of ear wax types, ear lobe attachment and tongue rolling ability. - Cruz-Gonzalez and Lisker - Acta Anthropogenet., 1982

The mode of inheritance of ear wax type, ear lobe attachment and tongue rolling ability were studied in 77 families with a total of 293 children. The results clearly showed that the dry ear wax type and the attached ear lobe type represent the homozygous state for two pairs of autosomal recessive genes. The evidence for the same being true regarding the lack of ability to roll the tongue was less conclusive in our material, but this could be due to difficulties in communication between the examined individuals and the examiners.

Tongue-rolling phenotypes and geographical variation in the United Kingdom

The distribution of tongue-rolling phenotypes in a sample (n = 477) of undergraduate students of the University College of Swansea (U.K.) was studied. The birthplaces of these students were also recorded. England was divided into six areas, and Wales was left as an area on its own. The data suggest that those students who come from north-east are more non-rollers, which may be due to mixture with Scandinavians.

Left-handedness and tongue-rolling ability.

948 undergraduates at The Ohio State University were administered the 10-item Edinburgh Handedness Inventory and asked to indicate the extent to which they could turn up the sides of their tongues. Significantly fewer left-handers than right-handers (62.8% and 74.8%, respectively) reported being able to turn up either or both sides. Sex differences in tongue-rolling ability were also noted. Among the 403 men included in the final sample, 77.4% could roll their tongues, whereas only 69.7% of the 491 women could do so.

This paper, however says (luckily Google finds a PDF here... seriously it should be illegal to have papers from the 70s behind paywalls... but I digress):
No evidence for a genetic basis of tongue rolling or hand clasping - Martin, J Hered., 1975

OCCASIONALLY one still finds in elementary genetics courses and elsewhere, the ability to roll the tongue and the manner of clasping the hands cited as examples of simply inherited human polymorphisms. This is despite extensive evidence to the contrary that has accumulated over several decades. Sturtevant T found that about 65 percent of persons studied were able to tum 1.JP the edges of the tongue and although some people were able to learn the ability, family data indicated that it was inherited as a simple dominant allele. However, Matlock reported 7 out of 33 monozygotic (MZ) twin pairs discordant for the ability, and Sturtevant concluded that there is sufficient nongenetic inftuence to make the character practically useless as a genetic marker. He confessed to being "still embarrassed to see it listed in some current works as an established Mendelian case."

The paper is also cited in the "Myths of Human Genetics" page of the University of Delaware.
So, all in all, it seems that there is evidence against a Mendelian transmission of this character, although these studies are quite old and some further analysis is warranted to exclude non Mendelian (read epigenetic) transmission of tongue rolling.


text:
Solubility of Forskolin in ethanol
I am interested in using forskolin in cell culture medium. Does anyone know how to make solution of 10 microM forskolin in 5% ethanol or less. I would like to avoid using DMSO as a solvent.
Thank you. L.

Sigma gives a solubility of 200 microMole in water containing 2% ethanol.
They state:

Forskolin is soluble in water (with 2% ethanol) up to 0.2 mM by first
  dissolving in ethanol at 5 mg/mL and doing subsequent dilutions with
  water.

The datasheet can be found here.

Thank you for you answer. We will probably try that,even though we tried to avoid the part where we would first dissolve it in absolute ethanol, as it gives some concerns toward inhibition of its ability to raise cAMP levels. Dont know if that is a genuine concern.

I don't remember the last time we prepared forskolin, but I don't remember this was a problem.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Hypothetically, what is the smallest functional form of human?
Since the my first encounter with doraemon manga, I've been wondering many things, one of them is the small light.
Assuming we had an instrument, such as small light, which enabled people to grow and shrink as they wanted to, what would be the smallest and the most compact functional form of a person?
First, I can rule out that we couldn't be as small as an atom because we couldn't be function as human being if we were compressed into 1 atom. So did 1 molecule. and so did 1 cell.
Second, you need more than 1 cell to construct organs, i.e. I couldn't imagine an eye which consists only several atoms or molecules.
Therefore, there should be a limit to the the size of human organs in order to fully retain their functions and thence, there should also be a limit to the minimum size of human organs.
What are the limits of size of each of human organs?
What are the limits of size of human then?

Not a real answer, but the smallest known primate appears to be the Phillipine Tarsier at 3.4" tall http://en.wikipedia.org/wiki/Philippine_tarsier  I would be surprised if there isn't a smaller primate hanging out somewhere.  If we were that small I doubt we would be able to drive a car or write television shows.  The brain case is quite small, so it kinda depends on your definition of humans.  eukaryotic cells don't shrink well. Hard question!

"Chandra Bahadur Dangi is the shortest man in history for whom there is irrefutable evidence, measuring 0.546 m (1 ft 9 1⁄2 in)."

This question is for Doctor Frankenstein!
The answer would depend on what you would accept to consider being a human.

Does it still need to be able to make simple calculation in order to be a human?
Yes, because otherwise we would have lost some functions. But then you may ask…
Does it need to have big enough hands in order to fulfill the social function of hand shaking.
Does it has to be attractive to the other sex?
Does it need a heart or is it fine if oxygen diffusion through tissue only is enough for this creature to live?

I guess that if you change the number of cells you will necessarily change the functionality. I am not saying that small guys are not as functional as big guys. For example, big guys are better runner, while small guys are better climber.

Are we allowed to shrink the cells to have minimal sized cells?
Are we allowed to shorten the DNA in order to shrink the cells?

Notes:

There are approximatively 200 different cell types in a human

My reference is not a peer-reviewed article (ref). Wikipedia lists cell types and it doesn't seem to go over 200. However, it is important to realize that it probably very much depend on how you define cell types.

Terminologica Anatomica lists over 7,500 names parts of the human body
There are 13 or 14 (depending on the gender) gland types
This article provides an estimation of the number of cells in the human body
Here (wikipedia) is a discussion on the concept of the minimal cell
Here and here (biology.SE) are discussions on the minimum number of genes/amino acid to sustain life
Here (biology.SE) is a discussion on which species has been found to have the smallest genome

Great answer. But only 200 cell types? I think that's a vast underestimation...

Thanks. I added a comment in my answer to explain why I picked 200 and clarify that this number might be subject to semantic issues.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What is the name of this tiny spider?
Found this spider on the flower bud in my garden. It measures about 5mm. I am from Kuching, Sarawak, Malaysia.

it's a jumping spider, there's some south east asian jumping spiders here: https://image.shutterstock.com/display_pic_with_logo/3499364/481322845/stock-photo-jumping-spider-in-southeast-asia-481322845.jpg

It looks like some kind of jumping spider, possibly an iridescent jumping spider based on your location (Family: Salticidae, Genus: Cosmophasis). Here is some information on it! https://en.wikipedia.org/wiki/Cosmophasis

Welcome to Biology.SE. You are more likely to get a positive response to your answer if you explain why your identification is correct. Specifically, please [edit] your answer to add discussion of key features that led you to this conclusion and supporting references or at least validated images. Without this your answer is indistinguishable from opinion. ——— Please also take the [tour] and then consult the [help] pages for additional advice on [Answer] and [Ask] effectively on this site.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Quantification of various amino acids from bacteria?
I would like to characterise how much of various (uncommon) cytosolic amino acids  are produced in bacteria, and was wondering if there are good suggestions of how to go about doing this. I know that chromatography is a good end-point analysis once I have isolated a fraction of what I suspect contains the amino acids; however, I am unsure about the smartest way to do the 'rough' initial purification prior to chromatography.
I know that you in general lyse the cells, pellet cell debris and then start some form of purification. I have also heard of certain resins that can bind natural products (e.g. Diaion® HP20, synthetic adsorbent resin) had thus aid the first purification step of the amino acids. Do people have experience with this? Are there also good solvents for separation of amino acids from lysate, that could be used in the first step (phase separation)? Does someone have any experiences with this? Any alternative suggestions would be appreciated.

Please clarify what you are trying to characterize. 1) You seem to be using amino acid and "natural product" as if they were synonymous, but amino acids are only one type of metabolite that you could call a "natural product". IMO "natural product" isn't a helpful categorization since it could refer to anything made by an organism — do you have a more specific definition? ——— 2) Do you have a defined list of what you want to characterize or are you interested in "fishing" for all molecules that fit certain criteria?

Yes, amino acids of various kinds (common and non common). I thought this would be specific enough? Amino acids is a type of molecule with the amine and carboxylate group on each end, and various side chain (depending of which amino acid it is). Overall they are very small molecules (under 300 g/mol).

I edited your post to something I find clearer — please [edit] if you feel that I've changed the essence of your question. Is there some reason you picked Diaion HP20? I had a quick look at the Sigma page for that resin and its description doesn't sound promising to me ...

Diaion HP20 is simply the only one I have head of, and the reasons I was asking what people think about it (or perhaps have head of something better?). Thanks for the edit - this is much better!

It sounds like you'll need to do a protein hydrolysis reaction to seperate the cellular proteins into individual amino acids. This book chapter compares different methods and their various pros and cons (https://link.springer.com/protocol/10.1385/1-59259-342-9:111). If you don't have institutional access, just find a paper that does a similar analysis to the one you want, and reference the methods. Just make sure they did a decent job of validating it before you used it. Published method does not always equal valid method.

A good approach could be to use GC-MS to identify cytosolic metabolites. When focussing on cytosolic amino acids, it might be useful to precipitate the proteins in a purification step and continue with the soluble fraction. Subsequently, a derivatization is done. The mass spectrometry helps to better identify the amino acids. This article by Phelippe et al. can give a good start.

Thanks, this was exactly the type of literature I was looking for! I filtered the lysate solution and I am now attempting a freeze-dry, to then resuspend it in some type of solvent that proteins dont like (might be a good way to completely remove them) - before e.g. GC-MS. I will have a look at the paper!

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Is there a difference between "genetic cross regulation" and "crosstalk"?
What is the difference between genetic cross regulation and crosstalk? I'm a physics major and learning about bioinformatics now. So it might seem trivial to many but from the article "Wanner BL. Minireview. Is cross regulation by phosphorylation of two component response regulator proteins important in bacteria? J Bacteriol 1992; 174:2053-8." I could not find a quantitative way to separate these two kind of gene regulations. Also, I would appreciate if anyone can suggest me something to read for further knowledge on this topic. Thanks!

Welcome to Biology.SE! You may find it helpful to take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site.

When learning about a new area I have found it helpful to start with a relatively accessible and reliable source like Khan Academy. Wikipedia can also be a good starting point and you can then check their references. Online platforms exist called MOOCs that offer free (or very low cost) courses on a wide variety of subjects — two that I am familiar with are Coursera and edX. Finally, textbooks with a good level of detail are also freely available online e.g. from NCBI.

I have never heard of “cross regulation” and it seems to be a term invented by the author of the review you cite, and which has never gained common currency. “Cross-talk” is not a specific regulatory mechanism, but a vague general term for the reciprocal interaction between two systems. As my Irish friend would say, if I wanted to get there, I wouldn’t start from here.

@David I have come across this term while studying some articles on systems biology. And those were very recent. One such article is "Zhou, X., Franklin, R.A., Adler, M., Jacox, J.B., Bailis, W., Shyer, J.A., Flavell, R.A., Mayo, A., Alon, U., and Medzhitov, R. (2018). Circuit Design Features of a Stable Two Cell System. Cell 172, 744-757.e17." So, you are probably right. The author may have coined the term "cross regulation"


text:
Is there any situation where bloodletting should be paired with transfusion?
Clearly, bloodletting only has benefits in a couple of rare instances —— for example promoting blood flow into reattached tissues1. But could it (or, should it) realistically be used along with transfusion for any purpose? Why or why not? (Based on Bradbury's Fahrenheit 451, where it mentions a blood transfusion/removal device)
1: Bennett-Marsden, M., & Ng, A. (2014). Hirudotherapy: a guide to using leeches to drain blood from tissue. Clinical pharmacist, 6.

Welcome to Biology.SE! This site tends to very exacting, so I would recommend you avoid statements like "bloodletting has been disproved", when you are really talking about its medical benefits. We also encourage you to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources). ——— Please also take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site and [edit] your question accordingly. Thanks!

I've made some edits that I hope will make this more acceptable to this community, but your question may actually belong on the [medicalsciences.se] site ...


text:
What kind of worm is this in my food? (Tuna sandwich from canned tuna)

Can I have some assistance identifying this worm which was in a tuna salad sandwich I purchased from a local co-op in Minneapolis MN?

Looks like a maggot (fly larvae) of some sort — see for example the following image:

That particular image is of a common green bottle fly maggot, which has a distribution consistent with your posted location.


text:
Identity of strange bird with fish net tangled around one foot

This bird was photographed at a small beach in Rio de Janeiro, Brazil.
What kind of (ocean?) bird is this??

Where was this photo taken? Also, great pic!

When asking for a specific species, you should give more contextual details like the country / region it was taken and the season (the question is not always related to the same time you took the pic).

Welcome to Biology.SE! In the future, please [edit] your posts to include all the relevant information in a visible format! Thanks!

This could be an immature black-crowned night heron, Nycticorax nycticorax.
Lines of evidence:

pale yellowish bill
thick neck
hunched back
orange eyes
head feather patterning consistent with "black crown" in adults

See these photos and captions published by the Cornell Lab of Ornithology:

Juvenile Black-crowned Night Heron
Thick-necked heron with a thick bill. Juveniles are brown and streaky overall. Note pale yellowish bill.
© Evan Lipton

Immature Black-crowned Night Heron
Immature birds have a mix of juvenile and adult plumage. This individual has faint streaking on the chest, a dark gray cap, and a nearly complete dark gray back.
© Alex Lamoreaux

Adult Black-crowned Night Heron
Stocky and compact heron. Often tucks neck into its body creating a hunchbacked look. Adults have a black cap and back that contrasts with its whitish to pale gray belly and gray wings.
© Jeff Timmons

Note the fishing line tangled around the adult bird's feet.  Must be a common trait!

Thanks for the replies. First, it took this photo from about 60cm distance to this bird with a 50mm prime lens. The bird did not move and i tried to speak calmly to it while robbing loser and closer, hence the pretty crisp image that looks almost like taken with a tele lens. Second: in my post there was some text box in which i entered the location - but once posted i did not observe this particular info was not visible. It was shot at a small beach in Rio de Janeiro, Brasil!

The tip with "Crowned Night Heron" seems to be accurate, the stocky slightly odd physiology is certainly spot on. The coloration of these birds seems to change according to age, that is somewhat confusing. I thought this particular bird looked already erh "old and wise", but judging by the colours it was only somewhere between juvenile and immature??

@RudMe — I think this is the correct id since this looks like a Black-crowned Night Heron, which is a common heron with a worldwide distribution. I encourage you to acknowledge Dirigibles work by accepting this well written answer. ——— Please also take the [tour] and then go through the [help] pages for more information on how to use this site effectively. Thanks!

Okay, done (i think). Did indeed not know about this as it is not obvious like it would be with some plain text link


text:
How does Propionibacterium acnes survive the antibacterial effects of sebum?
Sebum has antibacterial properties due to sapienic acid and oleic acid according to this article on sebum. According to the same article, desaturation of fatty acids increases acne development. Another article, also suggests that the free fatty acids contribute to the antibacterial properties of sebum.
How does Propionibacterium acnes survive the antibacterial effects of sebum? Does it lack the enzymes to break down lipids in the sebum to form the antibacterial free fatty acids?
Also why are certain acne medications are so effective simply by inhibiting sebum production? Is sebum actually metabolic fuel for Propionibacterium acnes?

Welcome to Biology.SE. The Biology.SE community has agreed that questions that show little or no prior research effort are off-topic on this site as are "homework" questions unless you have shown your attempt at an answer. Please [edit] your question and tell us where you've looked for answers, what you do know about the topic, and where exactly you still have questions. Under researched questions may be subject to down-voting and closure. Please take the [tour] and consult the [help] starting with [ask] for details.

In particular, how do you know sebum has antibacterial properties — providing references supporting such statements will greatly improve your question. Also note that you seem to have multiple loosely related questions — please post each question separately as this makes it easier to index (and find) answers on the site and also greatly improves your chances of getting all your questions answered.


text:
Is there an equivalent to vertebrate endogenous retroviruses in invertebrates or microbes?
I know jawed vertebrates have a lot of junk DNA floating around coming from ancient retroviruses. Some of the DNA is important to mammalian evolution. The DNA also provides a useful means to study the evolution of viruses.
I wonder if similar things happen for other lifeforms. I know parasitic wasps have a very interesting story even if I don't know the details.
I suppose even if viruses inserted themselves into microbes that microbes have much more pressure to have less DNA and so they may have gained genes but the evidence of junk DNA would have long ago been lost.
I suppose I'm asking: did ancient viruses insert themselves into other life in a similar manner to the endogenous retroviruses found in vertebrates and would we have evidence of it today in a similar manner?

I would not say that they are “equivalents” of endogenous retroviruses, but there are two types of elements in bacteria that bear some similarity.
Prophages
As some bacterial virus (phages) can undergo lysogeny as well as causing lysis of the host (e.g. phage lambda) it is not surprising that there are traces of phages in almost all sequenced bacterial genomes, although it is not always easy to detect and/or identify them unequivocally. This was reviewed by Casjens in 2003 who considered its significance in terms of the evolution of both phage and bacteria.
Of course, the structure of such phages differs from that of endogenous retroviruses and is generally much more complex.
Insertion Elements (IS)
To some extent endogenous retroviruses can be considered as retrotransposons elements, and this is certainly the case for the related LINE (L1) elements. So perhaps the bacterial insertion elements — the IS transposons — are worth mentioning. The structure of one class is shown below.

(Source: https://commons.wikimedia.org/wiki/File:Composite_transposon.svg)


text:
why do marine organisms orient with their bellies facing downwards?
why do marine organisms orient with their bellies facing downwards (like most creatures) given that they have relatively fewer constraints on their orientations than land or air organisms?

Maybe due to Counter-shading, a type of camouflage.  https://en.wikipedia.org/wiki/Countershading                                                             "A completely different function of animal (and military vehicle) coloration is to camouflage the top and bottom surfaces differently, to match their backgrounds below and above respectively. This was noted, for example, by Frank Evers Beddard in 1892:"

Also, keep in mind that the "belly" can be defined as the part that's pointing downwards in a horizontally-oriented creature such as a fish.

I'll address fish here. It's hard to tell which way is up with many sea-dwelling invertebrates, e.g. sea cucumbers. Sea urchins often are oriented "sideways" if you count their mouths as "down".
All animals normally orient themselves in the most advantageous manner dependent on their situation. Probably the most important determiners are field of vision and the inner ears, which work much like those of humans (who walk upright even if blind.) Unlike land vertebrates, the ear of fish is thought to have evolved as a vestibular organ for balance and orientation in space rather than as an auditory organ. Fish (and other sea creatures) also have other sensory apparatus which orient them, such as lateral lines.
Pipe fish swim in a horizontal manner like other fish, but rest vertically, swaying with the sea grass around it. Flatfish start "normal" but as the eye shifts position to the other side of the head, it will assume a bottom dwelling "sideways" position, with a contorted mouth and a fin squashed against the sand.

“Flatfish are the most asymmetrically-shaped vertebrate to ever live on earth,” says Alexander Schreiber, a flatfish expert at St. Lawrence University. “It sounds likes a really dramatic thing to say, but as far as vertebrates go, it’s true.”

Apparently flatfish brains start to receive stronger signals from one inner ear than the other.

Two organs — the eyes and inner ears — work together to keep typical fish in an upright swimming posture... If the eyes are not receiving the same amount of light on each retina... retinal neurons trigger the brain to tilt the entire animal and set it straight. ...As a fish’s vertical orientation in water changes, the brain combines information from the eyes and ears to figure out which way is up. ...[f]latfish larvae that are deliberately blinded adopt a sideways swimming posture.

When snorkeling, it is not at all uncommon to see any of a number of fish flip to their sides side to get a good look at you (floating above) with one eye, as opposed to maneuvering itself to face you. I imaging they assess the threat; since I wasn't a threat, they would just reorient themselves normally and go about their business.
Whatever aids survival within the parameters they are confined to (were born with) in that niche will be what you see.
The Improbable—but True—Evolutionary Tale of Flatfishes
The Vestibular System and Sense of Equilibrium in Fish


text:
Is 100% accuracy in DNA sequencing possible?
I would like to obtain a complete genome of a canine (with mitochondrial DNA too) at 100% accuracy. Is it even possible with the current technology? The source I have is potential degraded, i.e. dried saliva, dried blood, whisker root, fur roots, etc...

Can you explain what you mean by 100% accuracy. No technique is free of errors. Therefore we experiment a lot of times to improve the reliability.

Current DNA sequencing techniques are based on shotgun sequencing, randomly breaking the chromosomes into small pieces, sequencing the pieces (by various techniques), and then computationally reassembling the pieces by looking for overlapping patterns. This depends on sequencing each piece of DNA multiple times; the more coverage or depth, the more reliable the results. However, especially with long repeating base sequences, 100% coverage is uncommon with small genomes, and almost impossible with large genomes.


text:
What is this creepy little thing that I found sticking on my bathroom wall?

I found this creepy looking thing hanging on my bathroom wall. This is actually the 2nd time I have seen it. The first one I saw looked kind of dried up already stuck in between the walls. But this looks fresh and new. It's scary and gives me goosebumps just looking at it. Can somebody pls help

Welcome to Biology.SE! Identifications questions should include: 1) one or more clear closeup photos of the organism (photos from multiple angles if possible) — photos must be uploaded; 2) the location (e.g. country and region — the more specific the better) where you observed this organism; 3) an estimate of the size of the organism; and 4) the species-identification tag. I fixed 1 & 4 already, but please [edit] your post to include this essential information. ——— Please also take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site. Thanks!

This is the pupal stage of a lepidopteran (i.e. a butterfly/moth). The pupa is encased in the brown silken cocoon in the centre of the 'net'. The 'net' itself is built from the setae (hairs) of the caterpillar, which it sheds prior to cocoon formation.
Here's some photos of similar formations:

http://www.richard-seaman.com/Insects/Vietnam/Highlights/index.html#Chrysalis
https://www.nhm.ac.uk/wpy/gallery/2019-the-hairnet-cocoon?tags=ed.current
https://besgroup.org/2015/11/05/a-parasitic-fly-emerged-from-the-cocoon-of-a-footman-moth/


text:
What happens when you cook tree spinach with aluminum?
The Internet is filled with warnings that you shouldn't cook tree spinach(Cnidoscolus aconitifolius) in aluminum, because it will react and create toxins that cause explosive diarrhea when consumed. However, I can't find anything more specific than that. Does something (presumably hydrocyanic acid(HCN)) from tree spinach react with aluminum? If so, how does the resulting product cause diarrhea?

If aluminium is present in a hot medium wtih cyanide, perhaps it can produce aluminium cyanide?   i had a look at aluminium use as a catalyst in organic chemistry, it could be anything, there is however something called...Cyanosilylation: Aluminum alkoxides, such as aluminum isopropoxide (Al(O-i-Pr)3), are employed as catalysts in cyanosilylation reactions, which involve the addition of a cyano group to a carbonyl compound plus another group.


text:
Why do wild lizards often tap with their front leg?
I have a lot of wild lizards (possibly Podarcis muralis) in my garden, and I have noticed some of their behavior I'd like to understand:

whenever they are in 'still' position on any surface, they are quite often 'beating' with one of their front legs on the surface

in some cases they put the tail of the mate in the mouth

What is this behavior? Some kind of communication?

It would help to specify the species of lizard. If you don't know, can you provide some description, images or location?

Looking on various pictures on the internet I believe it might be something like Podarcis Muralis

I found a paper(1) about the 'tail in the mouth' behaviour in the whiptail lizard, Cnemidophorus ocellifer:

Every time that the female moved, the male followed her. During these periods, he often maintained physical contact, covering her hind legs and base of tail region . The male also performed a series of tongue-flicks on the female's back during this activity. During the observation, the female twice executed a sequence of two or three sinuous, figure-eight movements, which were confined to a small area, and after which, the female moved away. After each movement, the male remained motionless for a few moments and then resumed following her while foraging. After 45 minutes and nearly 15 m from their initial positions, the pair entered in dense underbrush, where we could not continue to observe them. While we observed the pair, there was no agonistic encounter between the accompanying male and other males for access or copula with the female.

The paper continues to explain this behaviour as simply a mating strategy:

Two conditional mating strategies have been described for teiid males (Zaldívar-Rae & Drummond 2007).  1) In consensual copulations,
the male courts the female, slowly circling her for several minutes,
then straddling her and copulating; this strategy is often performed
by a male companion, and thus is linked to accompaniment.  2)
Opportunistic copulations are not preceded by courtship, and are
characterized by a male chasing and holding a foraging female, and not
accompanying her after copulation (Zaldívar-Rae & Drummond 2007).

The 'taping the surface they are on' seems like an attempt to induce vibrations, which is a method of communication.(2)

Some chameleon species communicate with one another by vibrating the substrate that they are standing on, such as a tree branch or leaf. Animals that use vibrational communication exhibit unique adaptations in morphology (i.e., body form) that enable them to detect vibration and use it in communication. These include unique adaptations in ear and jaw morphology that give the animal direct contact with the surface they are standing on, and enable them to detect subtle vibrations. Lizards that live on substrates that can be easily moved (such as thin tree branches or leaves) are probably more likely to use vibrational communication than lizards that live on substrates that do not transmit vibrations as easily, such as the ground or thick tree trunks.

1- https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032011000400031#:~:text=The%20most%20commonly%20reported%20mating,Bull%202000%2C%20Ribeiro%20et%20al.
2- https://en.wikipedia.org/wiki/Lizard_communication


text:
How many of the four meiotic daughter chromosomes of a homologous pair can be recombinant via crossover?
In graphics I've seen, crossing over occurs between the "inner" two chromatids in a side-by-side arrangement of two duplicated chromosomes:
This suggests that only two of the four meiotic daughter chromosomes of a homologous pair can be recombinant via crossingover. Is this true? Or can you have more complex patterns, like the one below, in which all four daughters are recombinant? Does the X-shaped geometry of the doubled chromosomes play a role in models of crossover phenomena?

ps. Sorry if my terminology is strange. I'm a beginner! Experts: Edits to improve clarity welcome!

You appear to be assuming that your organism only has one chromosome. Since that is a highly unusual situation and may not be what you meant I encourage you to [edit] your question to make it clearer what you are trying to ask. One possibility is that you didn't mean gamete and you are actually trying to ask about chromosomes .... ———— Please also specify an organism or at least group of organisms — there are many variations on meiosis including some where no crossing over takes place!

Thanks for the advice, @tyersome! I hope it makes more sense now. I'm focusing on one pair of homologous chromosomes in a cell undergoing meiosis. I have drosophila in mind because that's what I've been reading about.

There can be and often is more than one crossover per chromosome in meiosis, but how many crossovers occur can depend on the species, sex, age, environment, and which particular chromosome is involved1,2,3. For example, humans typically show 2-3 crossovers per chromosome, but females often show higher recombination rates than males.
However, the structure you drew seems unlikely due to a phenomenon known as crossover interference, which suppresses the occurrence of closely spaced crossovers4,5. See also this historical introduction from Nature.
In Drosophila melanogaster, males do not make any crossovers6. In contrast, females show an average of around 1.2 crossovers per chromosome7. This means that most tetrads have just one crossover, but some will have more and this second crossover can occur between any pair of chromatids. Thus, there can be from two to four  recombinant chromosomes, but most commonly there will be two.
(Note that this last reference (7) is a 2018 review article on this subject and could be a good place for you to start learning more once you've mastered the basics of this subject — figure 1 in particular seems directly relevant to your question.)
References:

Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Meiosis. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26840/
Fledel-Alon, A., Wilson, D. J., Broman, K., Wen, X., Ober, C., Coop, G., & Przeworski, M. (2009). Broad-scale recombination patterns underlying proper disjunction in humans. PLoS genetics, 5(9).
Wang, Z., Shen, B., Jiang, J., Li, J., & Ma, L. (2016). Effect of sex, age and genetics on crossover interference in cattle. Scientific reports, 6, 37698.
Berchowitz, L. E., & Copenhaver, G. P. (2010). Genetic interference: don't stand so close to me. Current genomics, 11(2), 91-102.
Otto, S. P., & Payseur, B. A. (2019). Crossover Interference: Shedding Light on the Evolution of Recombination. Annual review of genetics, 53, 19-44.
John, A., Vinayan, K., & Varghese, J. (2016). Achiasmy: male fruit flies are not ready to mix. Frontiers in cell and developmental biology, 4, 75.
Hughes, S. E., Miller, D. E., Miller, A. L., & Hawley, R. S. (2018). Female meiosis: synapsis, recombination, and segregation in Drosophila melanogaster. Genetics, 208(3), 875-908.


text:
Please help me identify this caterpillar species (Sabah, Malaysia)

I kinda having trouble searching the internet to find this caterpillar name. Does anybody know what kind of species they are?

Welcome to Biology.SE! Cool looking caterpillars. To increase the chances of getting a correct id, identification questions should also include: 1) habitat information — for example what plant are they on; and 2) an estimate of the size of the organism. Please [edit] your post to include this essential information. ——— Please also take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site. Thanks!

If you can get a photo of just one of these from the side it may help even more; from what I can see these "caterpillars" are destined to become some sort of sawfly rather than a butterfly or moth (I think I see more than five pairs of prolegs on at least one of these--a butterfly or moth will have no more than five pairs of prolegs).


text:
Can someone identify this worm?
The first time I saw these was in an old cooler full of water by my shed, there were 3 of them about 2 weeks ago. Now tonight I found one crawling up my door. Can anyone offer some insight? I have dogs and I'm horrified that it may be some kind of parasitic worm that they can contract.
This was observed in northwestern Pennsylvania, US. Rainy, cool fall weather currently, as it's the end of October. They're about 2 inches long. Very thin, blackish red in color and extra wiggly.

Have you never before seen an earthworm?

Yes, an earth worm has that bump thing on it. They're generally fatter.

There are several species of earthworms. For some of them the "bump" is less pronounced and some are slimmer. Everything you report (occurrence after heavy rain) fits earthworms. The picture looks like one too. But photo quality isn't sufficient to be 100 % sure.

The "bump" on an earthworm (i.e., a worm species of the order Opisthopora) is a clitellum. Clitella are only visible on earthworms when they're sexually mature [Sources: 1, 2, 3]. So the absence of a clitellum does not preclude your specimen from being a member of this order.
The species in your photo is almost undoubtedly some species of earthworm. Without clearer images or more detail, I can't imagine someone taking the time to try to ID to species.
There are many species of earthworms present in Pennsylvania (though likely none of them are native to the US: see here). Keep an eye out for a recent invader, the "Asian Jumping Worm" [read more].


text:
What insect in shell is this?
Location: INDIA(Tropical Monsoon)
I found an insect (approx 7mm) (marked with red in image) in my bedroom hanging from the roof.

It can spin some kind of thread, since it was hanging at the first place
It has a shell like structure (marked with blue in image), and it stays inside the shell.

I forced it out of its shell. Its image is given below. I also recorded a video of its behaviours.

Please consider converting your video (or parts of it) to GIFs and adding them directly to this post. Sites like ezgif.com have simple tools for converting videos to gifs, trimming length, and optimizing file size. Including this info here would be beneficial. Thanks!

Does this answer your question? What insect is this? (India)

I'm almost certain it's a bagworm, or a moth larva in the Psychidae family. I'm no lepidopterist, I can't confidently narrow it down to genus or species level from there.

You are more likely to get a positive response to your answer if you explain why your identification is correct. Specifically, please [edit] your answer to add discussion of key features that led you to this conclusion and supporting references or at least validated images. Without this your answer is indistinguishable from opinion. Please also provide a citation/source for images. ——— You may also wish to take the [tour] and then consult the [help] pages for additional advice on [Answer] effectively on this site.


text:
What is this animal looking like an Axolotl?
My friend caught a strange looking animal and he's saying it is an axolotl. I keep telling him it's almost impossible, since they are almost extinct in their natural environment and he caught it in St-Larent River (Quebec, Canada)
Anyone have any idea what it is ?

Based on the size and location that appears to be a Common mudpuppy (Necturus maculosus). (Photo © Brian Gratwicke — CC BY)
The four toes visible on the front foot are also consistent with this identification.
This species is found throughout eastern North America and you can learn more about them from the Canadian herpetological society and iNaturalist.

@SamuelFyckes Note that just like the axolotl, it doesn't metamorphose to the adult stage - that's what makes them "strange looking" and similar. They're both salamanders that never "grow up".

I was thinking hellbender but I guess those don't live in Canada.

@prefectionist I'm definitely not an expert on amphibians, but a quick search suggests that the four-toed salamander is: 1) primarily terrestrial rather than aquatic, 2) much too small, and 3) looks nothing like the original photo. ———  If you have a better answer please post it — we need answers from experts, but that expertise must be demonstrated not just claimed.

Judging from the small limbs and overall size, it appears to be a large aquatic salamander, similar to Necturus maculosus, the mudpuppy. These have a pretty cosmopolitan distribution in North America, including into southern Canada. I can't tell from the photo if it has external gills.


text:
Why do individuals vary in the number of SNPs for a given gene ( e.g. FOXO3A )?
Individual #1, sequenced by 23andMe and then inputed into Promethease for SNP data has the following SNP output:
1) rs1935949(C;T)
2) rs2802292(G;T)
3) rs13217795(C;T)
4) rs13220810(C;T)
5) rs2764264(C;T)
6) rs9400239(C;T)
7) rs2153960(C;T)
8) rs2802288(A;G)
Thus individual #1 has eight reported SNPs.
Individual 2 also is sequenced by 23andMe and then inputed into Promethease for SNP data has the following SNP output:
1) rs2802292(T;T)
2) rs2764264(T;T)
Therefore individual #1 has eight reported SNPs for the FOXO3A gene and individual #2 has only two reported SNPs.
Since SNPs represent single nucleotide polymorphisms in the sequence, why does individual #2 only have two SNPs recorded rather than all eight?

Welcome to Biology.SE! We encourage you to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources). For "homework" questions, you are required to show your attempt to answer the question and to use the "homework" tag. ——— Please take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site. Thanks!

Why are there more brown-eyed people than blue-eyed people in Britain? Consider. It is the gene that exhibits polymorphism in the population, not the genome of an individual. The statement that someone has so many SNPs is incorrect. He has so many occurrences of the less common variant of a site that exhibits single nucleotide polymorphism. So your question is really why do individuals differ. I imagine you can suggest reasons for that.

Thank you for the welcome:I think my confusion is based on visualizing SNPs as single base pair substitution in the gene:
I thought SNPs can vary by basepair but not in total number - here 8 vs 2.  In the example rs2802292 is possessed by both individuals but with #1 carrying (G;T), and #2 carrying ( T;T) SNPs for rs2802292 which makes sense.
But, some rs #’s are only in person #1, such as rs1935949 (C;T).   So person #2 can have (C;C), (T;C), (C;T), or (T;T).  However #2 has no listing at all for rs1935949.  How can it be that no SNP of any type is present at location rs1935949? Thanks!

So, if I'm understanding correctly your question is why you aren't getting SNP information for all the variable positions? That seems like something to ask 23andMe about. IIRC they don't actually sequence DNA and so, due to the technology they use, I suspect that for some locations they may not obtain information.

Perhaps they don’t report an SNP if your base is the same as their reference genome.

Yes tyersome, my question is why we aren't getting SNP information for all the variable positions ( eight variable positions for individual #1 from the original example whereas only two from individual #2).  Your hypothesis does not appear to fit the situation however since individual #1 which has more variations reported also used 23andMe at the same time, so this does not appear to be a 23andMe issue?  Other ideas?
Canadianer - I am not clear this is the case since for other alleles ( besides FOXO3A we are discussing), 23andMe has reproted all (4) possible allele combinations at each SNP.

Not necessarily — for example, failures to detect information at a SNP could be due to an individual having an unusual sequence that the 23andMe technology can't "see" ...

Interesting point tyersome.  My understanding is that SNPs by definition correspond to only single nuceleotide substitutions as opposed to larger sequences ( ie those affecting >=1% of population).   Given that is the case it seems what the technology would only need to detect single nucleotide combination variants - (C;C), (T;C), (C;T), and (T;T) at that SNP locus.  The gene chip can detect any of those diploid combinations, so why would it be unable to detect which one of those 4 possibilities is present at that locus.

What do you think would happen if there was small insertion immediately adjacent to a SNP? How about a deletion of the region containing a SNP? I suspect uncharacterized or rare polymorphisms nearby might also interfere with binding to the chip. What happens if they expect C or T and you have G? I also don't think you can rule out technical problems at any level (e.g. a damaged/defective patch on the chip, dust in the detector, or software errors ...).

They have been sequenced several times via multiple companies & whole exome, so it sounds like it is on of the former suggestions you made in your last post.  As of 2015 it looks like there were at least 15 reported FOXO3A SNPs reported: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326903/   ...... It seems that having a deletion or non C/T nucleotide is far more likely to lead to reduced function than increased function ( being a rarity it is less likely selected for)......How unusual is it then for individual #1 to have only 8 and individual #2 to have only two of thoese 15 FOXO3A SNPs?


text:
Did the jackal (wild African dog) evolve independently or with some form of human domestication?
The jackal is a wild dog species in Africa that feeds on carrion, much like the hyena.
Pop science, as it were, would make us believe every dog species emerged as a result of human domestication. Was that the case for every dog species? Or might some have evolved independently?
Another way to phrase this would be: Do wild dog species have a completely wild heritage, or did they branch off of some previously domesticated line?

Welcome to Biology.SE! Please take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site and [edit] your question accordingly. In particular, this is a site for biology questions and your references to Egyptian mythology seem irrelevant (I will delete these). ——— We also expect you to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources). The wikipedia article on jackals is one place you could start. Thanks!

This answer is just for African golden jackal evolution, but this website (sciencemag.org) explains that...
“...researchers compared genomewide DNA samples from jackals, gray wolves, and dogs. They found that African golden jackals diverged from coyotes and gray wolves some 1.3 million years ago...”.
Also, this Wikipedia article about Canis arnensis (the Arno river dog) (I know that Wikipedia is unreliable but it had related helpful information) explains that...
“The Arno River dog has been described as a small jackal-like dog. Its anatomy and morphology relate it more to the modern golden jackal (Canis aureus) than to the larger Etruscan wolf of that time. It is probably the ancestor of modern jackals.”

Interesting, "wild dog" seems to be a misnomer then. It's more of a wolf species. Thanks for the input.


text:
How do evolutionary forces influence the number of copies of the p53 gene?
p53 is an important tumor suppressor gene. Around 50% of cancers are associated with loss of function in p53.
Humans have only two copies of p53 in their genome (one on each homologous chromosome). Elephants on the other hand have 20 or so copies of p53, and they also rarely die of cancer.
From an evolutionary point of view, I find it very curious that humans (and most other animals, I guess) haven't evolved more copies of p53 on their genome. Duplications of genes happen all the time, so there is variation in copy number for natural selection to work upon.
Are there known to be evolutionary forces at play (e.g. positive or balancing selection) which determine the differences in number copies of this gene between species?

Natural selection can only work on variability already present. Since there is only one copy of p53, I would suggest that perhaps a duplication of this gene is incredibly rare to start with, and even if we accept the premise that having an extra copy of p53 would prevent certain cancers, why would that measurably affect reproductive fitness? Remember that a part of natural selection involves surviving to pass on beneficial gene variants, or on the other hand not surviving to pass on detrimental ones.

I think this could easily be reframed into a very interesting question along the the lines of 'Do evolutionary forces determine the number of copies of the p53 gene in different species'. It seems a shame to be closed.

https://elifesciences.org/articles/11994

With the upvotes and edits I think there's too much community support for this question to have my unilateral close stand, so I've reopened. I'd hope that answers to the question would focus on the evolution of copy number of these gene in other species, and upregulation experiments in humans, rather than rehashing what we have already answered in https://biology.stackexchange.com/questions/35532/why-do-some-bad-traits-evolve-and-good-ones-dont

I agree with user438383, but think this needs more work on your part. In particular, a summary with references of what is known about variation of p53 copy number (and cancer prevalence) throughout animals seems needed. I think you should show that duplication of p53 is relatively easy and that increasing p53 copy number does suppress cancer (or at least correlates for more than one exceptional species). As a start I would read about this on wikipedia, in the paper linked above, and at Nature.

@BryanKrause I think you were right originally to close a question that is only answerable by opinion or challenging its premises, as has already been done for questions of a similar type.


text:
Standard cycles for virus detection
I would like to know if there is a Standard number of cycles for Virues and Bacterial PCR single and multiple targets

No, there isn't. It's completely dependent on the sample, how it was prepared, the quality of the template, and the viral or bacterial load in the sample. Try something, if there's no signal run more cycles, if the signal is overwhelming run less. That's science.

Or, run qPCR and study the amplification curves...

No, there isn't.
Quantitative PCR (qPCR) uses a specific (e.g. TaqMan) or non-specific (e.g. SYBR Green) dye to detect the point at which the quantity of dsDNA (or a specific template) exceeds a threshold during thermocycling. Assuming you have an appropriate primer, the quantity of target doubles (at most) during each thermal cycle, so the cycle at which the signal exceeds the threshold (the cycle threshold, or Ct value) gives you information about the amount of target initially present.
However, the amount of accessible target in a sample depends on many factors including sample processing, extraction efficiency, sample storage, or the presence of RNases/DNases. The PCR efficiency during cycling also varies depending on conditions. There are also many other sources of variation in qPCR results, for example the platform you're using, the risk of contamination, the cycling program.
In theory, you can keep running a qPCR until you get a signal, but in practice you would stop after about 40 cycles at most unless you were specifically designing an assay to detect extremely low copy numbers since after that the most likely explanation for a positive result is sample contamination. 40 cycles should be enough to detect a template that was only present at 1/1,000,000,000,000 of your detection threshold to begin with. When designing qPCR experiments purely for detection (as opposed to quantification) it is best to include a negative control which helps rule out sample contamination etc. I recommend reading the answer to this previous question to help understand why we stop after a certain number of samples, and see this paper as an example of the risks of not using an appropriate control.
There is some guidance on designing good qPCR experiments at http://www.rdml.org/miqe.php along with a checklist for best practice (although this is specifically aimed at quantitative qPCR studies so not everything on their checklist will be relevant if you are simply thinking about presence/absence).


text:
Is chromosomal DNA more likely to interfere with restriction mapping or PCR analysis in E. coli?
We are characterizing YADH-1 in my biochemistry lab course. Over the course of the first weeks, we harvested E. coli cells, and isolated plasmid DNA via alkaline cell lysis. A previous exam for the course asked the following question concerning plasmid DNA and analysis:
"Is chromosomal DNA more likely to interfere with restriction mapping, with PCR analysis, or equally likely to interfere with both methods?"
Since we're using EcoRI and BamHI, my thought process is that while we can predict the cuts on a circular plasmid, we wouldn't be able to predict all of the cuts on high-molecular weight chromosomal DNA, and the resulting restriction map would be useless. However, PCR can work in a complex mixture of molecules, so even in chromosomal DNA, the primers should be able to find the target sequence. Is the answer therefore that chromosomal DNA is more likely to interfere with restriction mapping?

Welcome to Biology.SE!
I think you've come to a reasonable conclusion, but not for exactly the right reasons.
The genomes of several strains of Escherichia coli have been sequenced (e.g. https://www.ncbi.nlm.nih.gov/nuccore/U00096) so you could predict the sizes of the fragments you would expect from your digest.
The genome size of E. coli is about 4.6 million base pairs and six-cutters like EcoRI and BamHI cut on average about once every 4096 bp (you should be able to figure out how to come up with that number). From that what would you expect to see if you did a restriction digest on this bacteria's genomic DNA?
Does that help you improve your answer?
(If you have access to the appropriate software, I encourage you to download that sequence and check your conclusions.)
((Also note that the specificity of PCR is dependent on primer selection, so your answer is assuming that the primers were well designed!))

Ah, it does. That means I'd get about 1100 different cuts on a map for genomic DNA, and wouldn't be able to conclude if I'd isolated the gene of interest.

Yes and each of those fragments will be a different size!  I found a relevant picture here: https://www.semanticscholar.org/paper/DNA-Probe-for-Lactobacillus-delbrueckii.-Delley-Mollet/27223427d914f7ccca92c43937d83eadbddc1963/figure/0


text:
Concentration of active ingredient
For some time now, I have been wondering why, when a tablet is taken, the concentration of active ingredient undergoes an exponential decrease after the maximum concentration value in the blood is reached. For the model I refer to see.
Are there any biological reasons for this, that someone with no biological background is able to understand?

Exponential decay is a commonly observed phenomenon in nature where the rate of decay is directly proportional to the amount of stuff you start with. If you have twice as much stuff, it decays twice as fast, etc.
Another way to say it is that every molecule has an equal and independent chance of decay.
Radioactive decay is often taken as the "standard" model for exponential decay. Any unstable atom has a chance at every moment in time to decay to a more stable state. Other atoms in the universe don't influence the rate, it's just an intrinsic property of each separate atom that it has some chance to decay.
In pharmacology, the exact mechanism depends a bit on the molecule, but let's imagine a drug that's metabolized in the liver. If the drug is in a relatively low concentration (as most drugs are once they reach the bloodstream) as are it's metabolites, then the rate limiting step is the chance of an interaction between a molecule of the drug and whatever enzyme catalyzes the reaction to the metabolite. If the concentration of liver enzymes remains constant, and the low concentration of drug means there is no appreciable saturation of those enzymes, then you can think about this chance interaction as being an independent chance for each molecule of the drug. If you have twice as many molecules of the drug, you have twice as many chances for them to interact with the enzyme for a given time step.
For something filtered by the kidney, you could think exactly the same way: it's the chance of each individual molecule being filtered into the urine. Twice as many molecules means twice as many chances to end up in the urine.
Not all drugs follow this pattern. Few drugs are in high enough concentrations for the drug concentration to matter, but some are. Ethanol, for example. Other drugs have more complicated metabolic fates, induce enzyme activity that influences metabolism, or accumulate as waste products that reduce decay. There are also drugs that partition strongly into other compartments and you might need to consider different routes in which a drug might eventually leave the system.


text:
Was there ever a very first Homo sapiens?
My friend keeps saying that there was a first Homo sapiens. Meaning, there was a very first human being that was ever born.
I can't really understand what she means to say from a selection/gene mutation perspective. I can't understand how there would be anything that could be considered the very first human being.
Was there ever a very first, singular human being that could be discerned as such?

Perhaps she is referring to mitochondrial eve or a "common-ancestor of all people alive today" which is popular with journalists, although it's thought that the human population has never had less than a few thousand common ancestors.

She means to say the quite literally "someone had to have given birth the the first human baby," just as a logical deduction. There are humans, therefore the must have been a first human baby. So, something gave birth to the very first homo sapien.

perhaps ask her who made the first car? what was the first pet dog that wasn't a wolf?

Is there some reason you uncorrected the spelling and capitalization of Homo sapiens to "Homo Sapien"? If you insist that is correct please provide a reliable reference that supports that usage. Thanks!

I didn't realize it was corrected since no one posted an edit comment. Since I have other misspellings (doing this from my phone), I assumed I had accidentally left it in the lowercase. I didn't realize that the term is lowercase

Yes, for binomial names the genus is always capitalized and the species (and subspecies) are not. ——— On a phone you should still be able to see that a post has been edited and the word "edited" will be a link that takes you to a page that shows you the edit history. ——— You might find it helpful to take the the [tour] and then go through the help pages starting with [Ask] questions effectively on this site to become more familiar with how the site works.

No. It is important to distinguish "species" as a human system of classification, and "speciation" as a biological process. Except in cases like chromosomal speciation (changes in ploidy), speciation takes a long time. Probably thousands of years between some initial restriction of gene-flow, and fixation of a specific identifiable trait, present in all individuals of a species, and not present in any others. As a human system of classification, the taxonomists who define species would all understand that speciation is a process that occurs over time, although they may make some arbitrary distinction for convenience. For example, a node on a cladogram symbolizes an instantaneous process of species bifurcation, but this is understood to be an unrealistic simplification.

Thank you. While I didn't have the background, I was pretty sure that was the case.


text:
How did interspecies reciprocity involving cleaner wrasses originate?
The small bluestreak cleaner wrasse (Labroides dimidiatus) will approach a much larger fish (for example a grouper such as Cephalopholis miniata), enter its mouth, and spends several minutes cleaning its teeth. How did this behavior evolve? Wouldn’t the first cleaner wrasse that was bold enough to approach a larger fish have been immediately eaten? Since, in this encounter, the behavior of both fish isn’t learned, it must be encoded in their genomes. How could the appropriate coding gradually evolve?

Cleaner wrasse don't only clean within the mouth; although some species may specialize towards mouth-cleaning, it's likely that this behavior began with cleaning elsewhere on the fish's body.
Some studies (e.g. Bshary, 2003) suggest a large effect of cleaners on fish populations/diversity, so it seems that there are strong selective pressures for evolving behavior permissive to cleaning fish.
The cleaners themselves seem to have evolved cleaning traits on many occasions (see Baliga & Law, 2016). Although there are some obligate cleaner species, it's more common for cleaners to clean as juveniles, and the most common transition between cleaner behaviors is from non-cleaners to juvenile cleaners.
Therefore, it seems like the first cleaners were very small fish outside the typical prey target size of the cleaned fish. If there is strong selection towards individuals who tolerate these small, non-prey cleaners, it's reasonable to expect that this behavior could expand towards larger cleaners, and eventually to the more extreme versions of the behavior like allowing cleaners in the mouth.

Baliga, V. B., & Law, C. J. (2016). Cleaners among wrasses: phylogenetics and evolutionary patterns of cleaning behavior within Labridae. Molecular phylogenetics and evolution, 94, 424-435.
Bshary, R. (2003). The cleaner wrasse, Labroides dimidiatus, is a key organism for reef fish diversity at Ras Mohammed National Park, Egypt. Journal of Animal Ecology, 72(1), 169-176.

How are specific behaviors learned during one's life encoded in the genome of germ cells so they can be passed on to offspring?

Specific behaviors learned during one's life are not encoded in genomes, and there is no implication that that's the case here. Behaviors, and tendencies toward behaviors, can be genetically encoded and selected for. This is a very different question than originally asked, and should be asked separately (though I think it has already been asked and answered on this site)

@igorbrznovskaya For an example of the sort of thing that can be learned during the lifetime, think about a human's preference for a treat, let's say ice cream. The behavior of seeking out ice cream is indeed a learned behavior, but the evolved part that is transmitted in the genome is the preference for fats and sugars. Similarly, there is some underlying evolved behavior here (perhaps the physical sensation of being 'cleaned' is pleasurable? like scratching an itch), but there may be learned components ('fish that look like this scratch itches').

The behavior is beneficial for both species. To use your explanation, perhaps the first L. dimidiatus that was bold enough to approach C. miniata was immediately eaten, but some proportion of C. miniata did not eat the L. dimidiatus, and the alleles responsible for the cooperative behavior increased in frequency for both species, while the alleles responsible for the non-cooperative behavior decreased in frequency.
See symbiosis


text:
Bed bug or booklouse?
I found this creature climbing on the lower part of a wall inside apartment. Can you distinguish if it's a bed bug nymph or a booklouse? Sorry the photo quality isn't great, because it's so small (2 mm). Thanks in advance!

See Insect identification - Is this a bedbug? for more information about bed bugs

After looking it up, I can, with some confidence, confirm that this is a book louse in the larval stage, as seen in this picture:
https://bpca.org.uk/write/MediaUploads/Pages/A-Z/Booklice/booklice-1.jpg
I hope this answers your question!

you should add a link about bedbugs to ilustrate the difference of the two species.https://en.wikipedia.org/wiki/Bed_bug


text:
Explain a transpiration graph

The solution is A, but I think both A and C are correct. For choice C, stomata that protected by hairs will have a greater amount of water vapour around them, hence lower water potential gradient. Hence, this results in the reduction in the rate of transpiration, as well as choice A.

Though I don't come across graphs like these too often, I guess the answer should be A because...
From the graph, it is clear that Leaf 1 has more mass than Leaf 2 after 5 hours. This means there is a lower rate of transpiration in Leaf 1, which can definitely be explained by a thicker cuticle (since the thicker the cuticle, less is the water lost). Hence choice A is correct.
Now, look at choice C. Like you said, in leaves where stomata are protected by hairs, there will be lower rate of transpiration. Then, obviously Leaf 2 should have a higher mass than Leaf 1, right? But this is not the case (as per the graph). Hence, choice C is incorrect.


text:
Hair becoming white in one night after tremendous stress
You have surely heard about soldiers during the war whose hair became white in one night due to the tremendous stress.
I was wondering how is this possible biologically ?

Are there any documented medical cases of this? Without them, these stories are just hearsay. Stress does contribute to gray/white hair - just look at before and after pictures of the last 4 or 5 US presidents. However, this does not, and from a physiological perspective cannot happen overnight.

The physiological condition you are looking for is commonly called Marie Antoinette Syndrome.
Under extreme psychological stress, the hair of the person does turn white but not in a single night (takes place slowly over successive days; in a matter of weeks) and cases of this has been reported worldwide generally in warzones.
Contrary to what you suggest, this phenomenon is extremely rare and I doubt many soldiers experience it.
Source- http://archderm.jamanetwork.com/mobile/article.aspx?articleid=712060
Another interesting tidbit the author mentions is whether Marie Antoinette herself suffered from it or not. The author goes in depth on the topic; regardless the syndrome is definitely real with documented cases. It is also known as canities subita.
Most in the scientific field now refer to it as an acute episode of diffuse alopecia areata. Alopecia areata is patchy hair-loss. This syndrome is referred to as such because the white hair eventually fall off.

Could you add a source to that?


text:
Can we apply NGS (next generation sequencing) on DNA extracted from formalin fixed paraffin embedded tissues (FFPE)?
I'm working on the microbiome and I can only use tissues which are fixed with formalin and embedded in paraffin. Is it possible to apply NGS (next generation sequencing) on FFPE (formalin fixed paraffin embedded) tissues? I'm particularly concerned about contamination that could affect the results.

Welcome to Biology.SE! Please take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site and [edit] your question accordingly. In particular, the wording of your last sentence was very unclear — I've rewritten it and corrected many errors, but please check carefully to make sure that I have not deviated from your intended meaning. ——— We also encourage you first to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources). Thanks!

It's a little hard to tell based on your question, but it seems that you want to do Illumina sequencing of FFPE tissue samples. This is quite routine, Illumina sells kits for it.
I do not know how the FFPE process affects microbial cells, but people have published recently on doing metagenomic analysis of FFPE tissue samples. This suggests to me that it is possible.
If "any contamination" is a problem, then maybe there are additional roadblocks; low-level contamination is a routine problem in metagenomics, which is exacerbated by complicated, old, or low-input sample types. I would suggest treating it the way you would treat any other metagenomic sample, and try to exclude the possibility of contamination through methods and account for it in data analysis.

Thank you very much , yes i have fears about paraffin and its remove could cause any artificial mutations in the DNA , it  can be a real problem for the sequencing process.

People have been doing FFPE sequencing on Illumina instruments for years. Literally a decade, I believe.

@swbarnes2 oh yes, it is quite routine as i said. I think that the only question is how viable/mature it is for metagenomic sequencing.


text:
Do conservation oriented genetic database exist?
Are there any projects for the creation of the international genetic database of all endangered species, so we, at least, have a chance to clone them in the future if our current conservational efforts fail?

Welcome to Biology.SE! I assume you meant conservation rather than conversation? Please take the time to go through the [tour] and then the help pages starting with [Ask] questions effectively on this site. Thanks!

First, it isn't entirely clear to me why you would want such a database.  Essentially all sequences are available in one (typically all) of the big databases.
For example if I search the NCBI database for "extinct" I get this.  There will be many more sequences for species that are "only" endangered.
Second, having a genome sequence isn't sufficient for "de-extinction" of a species.  The reasons for this are beyond the scope of this question, but can be explored starting from this section of the wikipedia article.
You will likely also find this discussion to be of interest.


text:
Can you help me identifying this spider?

I took this picture in Ohrid, Macedonia, it is the first time I see this kind of spider here.
This spider was 2-3 cm long and was outside in urban building.

It's probably an Araneus, but I'm not sure about the species.

Welcome to Biology.SE! Thank you for including location information, but please edit your post to add an estimate of the size of the spider and the environment you found it in. —— The size and environment can be essential clues for identification. Thanks!

It was 2-3 cm long and it was outside in urban building. Thank you too

@CveteRisteska Better edit your question and insert the size and location information in the original post. Information in comments might get lost or people won't read them.

I tried to identify it by your photo via Seek app and the result is "cross orbweaver / Araneus diadematus
The result seems true when it's compared to description in this site
For comparision see this image:

You're welcome. I strongly recommend this app for that kind of situations.


text:
Absent gene expression from one of two vectors co-transformed into the BL21(DE3) strain of E. coli
I've been trying to express two proteins in the BL21(DE3) strain of E. coli.
One gene is in a pCR2.1 vector and the other in a pET-expression vector. When I induce with IPTG and run on an acrylamide gel I only get the protein encoded in the pCR2.1 construct. If I transform the BL21(DE3) cells with each vector independently (only one of the plasmids in the cells) I can get expression for either protein.
Does anyone have any Idea why I wouldn't be able to induce expression from the pET vector in the double plasmid strain but can induce expression from either vector in single plasmid strains?

I edited you post in a way that I hope makes things a bit clearer. ——— Some suggestions for [edit]s to your post that may help you get a better answer would be to include answers to the following questions: 1) How are you ensuring that both plasmids remain in the co-transfected cells? 2) What are the proteins you are expressing and are they known to interact with each other in any way? 3) Would the way you prepare your protein samples for PAGE effectively solubilize proteins that were in inclusion bodies?

the use of two antibiotics kanamycin and  chloramphenicol, 2)the proteins being expressed are NPR1 in the pCR2.1 (protein related to systemic acquired resistance in arabidopsis) and TGA3 a transcription factor in the pET vector. The two proteins have been shown to interact in Y2H. But didn't interact in the pull down assay since the TGA3 wasn't induced. 3) I don't think it has anything to do with insoluble aggregates since in the single plasmid strain we see the TGA3 protein. Thanks @tyersome .


text:
Is α-keratin a fully functional protein?
Is α-keratin before it coils with another polypeptide, makes chains, and build intermediate filaments a fully functional protein?
I mean, is the single monomer of α-keratin a protein or does it have to become a dimer to become a protein?

This question appears to be answered in the wikipedia article on α-keratin ...

What we call as protein is the final quaternary structure. Whether it is translated from a single gene or from multiple genes (as in haemoglobin), always the structure with all bonds and interactions taken into account. Similarly here the alpha- Keratin forms Disulfide bonds to form a functional protein.


text:
Do most bacteria have plasmids?
Do most bacteria have plasmids?
I googled that and I found this

Yes, Plasmids naturally exist in all bacterial cells. Here

But I know some of them don't!
Is this sentence scientifically correct?

Most bacteria have plasmids. If you study a random bacterium, you will probably find plasmid(s) in it.

I am voting to close this question as it is not a question about biology (nor even one about scientific terminology) but about use of the English language. It might be appropriate on [ell.se].

Ignoring the grammatical quibble for now - how do you know that some bacteria don't have plasmids?

@MattDMo I know that from my textbook, I added a picture.

I think there might be some confusion between individual bacterial cells and "Bacteria" in general. The link you shared is either oversimplifying to the point of losing touch with the truth, or they simply used inappropriate word choice. It's unfortunate that they didn't seem to include a primary source to backup that claim.
For a more general statement like, "Most bacteria have plasmids," I would interpret that as meaning plasmids have been found in most bacterial lineages, not necessarily that most individual bacterial cells have plasmids. But I could see how that might confuse some readers and/or educational content creators.
I will share this for reference. The distribution of plasmids is typically heterogeneous within populations, and variable between populations. For any given plasmid, it's common for only a fraction of the population to carry it. Sometimes nearly 100% of a population carries has the same plasmid, but in other cases it can be 10% or less. I would wager that it depends on how mobile that plasmid is and on the selective pressures specific to the environment in which they are living.
I have personally observed this heterogeneity even in laboratory strains under antibiotic selection. I once determined that less than 20% of my E. coli cells in a culture were actually carrying the plasmid under selection (I did this quick experiment because I was not able to recover detectable amounts of the protein that I was trying to express in my strain).
The reference I linked might be a useful resource for the OP. In case that link doesn't work, here's the reference.
Holger Heuer, Zaid Abdo, Kornelia Smalla, Patchy distribution of flexible genetic elements in bacterial populations mediates robustness to environmental uncertainty, FEMS Microbiology Ecology, Volume 65, Issue 3, September 2008, Pages 361–371, https://doi.org/10.1111/j.1574-6941.2008.00539.x

When people work with E. coli in labs, they often use a strain initially without plasmids - which is very easily infected if someone else nearby is working with a strain that does have a plasmid.

So if we leave the lab, it is pretty unlikely to find a bacteria without plasmid(s) in nature, isn't it?

Uncertain, I dont know if a survey has been made.

@AmirhoseinRiazi - Plasmids are commonly found in natural bacterial populations. See the link in the answer I posted for more information.


text:
Weird spiky bug found in northern Spain
Does anyone know what this bug is? We're located in the north of Spain. Around 5mm long with spikes in its back.
First image is belly up, second one the bug is walking.

The second photo looks almost exactly like the first, except blurry and without a shadow. Is that a mistake? Can you take a clearer photo of the dorsum (back) of the bug? Closer would be great! Thanks.

Sorry, they're not mine and the bug is no more. Supposedly the second one is the dorsum of the bug. I'm another site someone suggested it found be a cordyceps infected bug (didn't know the bug's species though :(

OK, I'll assume that because there are no legs visible adjacent the surface where there should be, this is just another picture of the upside down bug. The chances that there would be such a symmetrical multiple cordyceps infection are remote, to say the least.

Oh, then back to square one  it's a shame there aren't better pictures.


text:
Repair of cloning vector nicks digested with antarctic phosphatase and ligated with T4 enzyme
The vector product obtained by ligation between a vector previously digested with antarctic phosphatase lacks 5' phosphate groups. T4 ligase can ligate it to an insert with complementary sticky ends which provides 2 phosphate groups. But there are still 2 nicks in the vector product! How are these normally repaired ?

The nicks are not repaired during preparation. Instead, the vector (which is circular, despite the nicks) is transformed into the host where it is repaired by endogenous mechanisms, likely through base excision.

Why was this down voted. Am I wrong?

Yes it is possible. However the efficiency reduces. I had seen someone doing it for site-directed mutagenesis. So transforming the plasmid without sealing nicks does produce colonies but they were less than the case when the nicks were sealed. <I don't know the reason for downvote>


text:
Are there land animals that use gill-like organs instead of lungs?
Among aquatic, water-breathing animals, gills and other continuous-flow breathing methods dominate over lungs and other storage-based breathing methods as in land animals. Notably, axolotls have gill-like structures around their heads which use a high surface-area structure heavily vascularized with capillaries to breathe water.
However, it seems all air-breathing organisms use storage-based breathing, air-breathing fish included, as lungfish use their swim bladders as lungs, a clear example of storage-based breathing.
Are there any land organisms that use continuous-flow breathing methods over lungs?

That emphasizes that fish with only gills would have had much difficulty in adapting to land for the same reason that electric tyre pumps and manual tyre pumps are different.

Terrestrial crustaceans are land animals that use gills (or gill-like structures) for gas exchange, though these gills must be kept moist for efficient respiration.
Specifically, animals like hermit crabs have a branchiostegal lung that looks like gill tissue but is better adapted for absorption of oxygen from air instead of water.

Some terrestrial hermit crabs (genus Coenobita) have gills, but these are only partially responsible for their respiration1. These animals carry around water with them in the snail shell they 'wear'.
Amphibious land snails in the genus Pomatiopsis have gills2.
Finally, a terrestrial amphipod known as a "sand hopper" Talitrus saltator also has gills3.
References:
1: Farrelly, C. A., & Greenaway, P. (2005). The morphology and vasculature of the respiratory organs of terrestrial hermit crabs (Coenobita and Birgus): gills, branchiostegal lungs and abdominal lungs. Arthropod Structure & Development, 34(1), 63-87.
2: Burch, J. B., & Van Devender, A. S. (1980). Identification of eastern North American land snails: The Prosobranchia, Opisthobranchia and Pulmonata (Actophila). Museum of Zoology and Department of Ecology and Evolutionary Biology, The University of Michigan.
3: Ungherese, G., Mengoni, A., Somigli, S., Baroni, D., Focardi, S., & Ugolini, A. (2010). Relationship between heavy metals pollution and genetic diversity in Mediterranean populations of the sandhopper Talitrus saltator (Montagu)(Crustacea, Amphipoda). Environmental Pollution, 158(5), 1638-1643.

Modern reptiles (including birds, but possibly excluding turtles) have a continuous flow system of lungs. In birds, the lungs have air pushed over their lungs by larg air-sacs, similarly to how water is pumped over gills by the mouth in fish


text:
Is this bark beetle going to be a problem?
This little (around 3mm in length) beetle is one of many that infested a gingerbread heart in our house. It seems to be some kind of bark beetle. My question is what exact species it is likely to be and whether it is a danger to our wooden floor, furniture, maybe even roof. We live in Germany.

Stegobium paniceum. (Biscuit beetle, bread beetle, drugstore beetle).

Copyright Siga, via Wikipedia, CC BY-SA 3.0 2022.

Copyright marked, via entnemdept.ufl.edu, fair usage, 2022.
Characteristics:

Adult can be up to 3.5 mm in length.
Worldwide distribution though it is more common in warmer climates.
Notched antennae (like the teeth of a saw).
Diet consisting of a diverse range of dried foods and spices, as well as hair, leather, books, birdseed, dried pet-food, and museum specimens. The drugstore beetle is also known as the biscuit or bread beetle since it can live on biscuit or bread crumbs.
Larval form is a small, white grub. Period in this phase can be several months. Larvae do most of the damage this creature causes (great economic harm).
Likely to eat through foil-sealed food packaging.
Lives in obligatory symbiosis with a yeast fungus.

Pest control measures:

Thorough cleaning.
Destroy infested material.
Freezing below -20 Celsius (-4 Fahrenheit).
Diatomaceous earth sprinkled in corners may help.

Resembles, but not to be confused with a related species:
Anobium punctatum. (Common furniture beetle, woodworm).

This seems almost certainly correct. Not sure this is great news, but at least it's not going to bring down the house.

I taught Latin grades 3 -12. That was the magistra in me bursting out, sorry. :-/

Not at all. It's just that no-one taught us about pre-classical Latin. Never even thought to look anything from that period up before. I'm all too glad to learn. @anongoodnurse

I really like the etymology of words (English, Latin, French, Norse, whichever.) It never occurred to me to stop at some arbitrary line.

For me, it's not so much that I stopped at a line, just that I've been given snapshots of languages at school, and I've continued taking them, increasing the range of languages as I go. Hadn't gotten around to looking at what came before Catullus, Cisero etc., except when looking at Ancient Greek words that get kicked-up in English from time to time. My paternal aunt is the real linguist of the family with her Russian, Spanish, Italian, Bulgarian and a heavy dose of comparative linguistics. Weird to think that she never used it in any of her jobs. @anongoodnurse

Wow!!! Kudos to her, seriously! French was my first language, so the Romance languages are easy (Well, not Portuguese) and Latin, of course, informs those. Kudos to you, too, for following Greek. Once the letters change shape, I wimp out. :( Only used French twice in my decades as a doc. Spanish? Nearly every day.


text:
Evolution of hunting behavior of parasitoid wasps
Wasps in the genus Pepsis lay their eggs in a specific region on a species of tarantula and their larvae eat the tarantula organs in a specific sequence to keep it alive as long as possible.
How could this process have evolved, considering that a mistake at any stage results in death?
This is the description of the egg laying behaviour:
Upon finding a tarantula, the wasp locks its mandibles onto a foreleg and brings its stinger into position so as to paralyze it.
During this process, the tarantula tries unsuccessfully to dislodge the wasp, but the wasp ultimately locates the right part of the tarantula in which to insert its stinger.
Upon inserting it, the wasp injects a venom that paralyzes the tarantula. Note that the tarantula is ten times the weight of the wasp, so the wasp takes very big risk in trying to attack such a tarantula.
The wasp then drags the tarantula into a hole that it has already dug. It pulls the tarantula down into the  hole, attaches its egg to a specific part of the tarantula's body and then covers up the hole so that predators won't find it.
When the egg hatches, the larva eats the organs of the tarantula in a specific sequence so as to keep the tarantula alive for several weeks. Eating in the wrong sequence results in the death of the tarantula, and its subsequent putrefaction, which means the death of the wasp larva.
When the larva successfully eats in the right sequence, it is able to obtain enough nourishment to prepare for metamorphosis, ultimately resulting in a full-grown wasp, which then exits the hole and becomes a predatory wasp.
These wasps are solitary, which means there are no conspecifics to teach the new wasp how to do all this.
Thus, the entire behavioral program described above must be encoded in the wasp's genome.
The description above is based on:
Punzo, F. (2005). Experience affects hunting behavior of the wasp, Pepsis mildei Stål (Hymenoptera: Pompilidae). Entomologica Americana, 113(3), 222-229.
Petrunkevitch, A. (1952). The spider and the wasp. Scientific American, 187(2), 20-23.

Please use paragraphs to make text legible to people, especially with complicated phrases. The question could be only 2-3 lines. It's a bit like AI. Evolution is usually about gradual change, so the wasp has always followed a path which has given it good survival rates. The behaviors become complex over time, from simpler to more complex.

Welcome to Biology.SE! This is an interesting question, but I suspect very hard to answer in just a few paragraphs. We encourage you to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources) or even answer your own question. For example, I found several freely available review articles on this subject by searching using your title. ——— Please also take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site. Thanks!

@com.prehensible and tyersome thank you for editing my question.

While it doesn't directly address this particular example, you should find this related question and answer to be of interest. In general, complex behaviors (and structures) evolve over very long periods of time as improvements on simpler behaviors. A look at related wasps with simpler "lifestyles" should help you understand how such an "optimized" (note it is probably sloppier than you think) behavioral program can evolve.

@com.prehensible Please show me how you can simplify this behavior.

The common ancestor is thought to have laid eggs on or in wood grubs 247 million years ago. Since then they have evolved into as many as 500,000 species, mostly with a specifif host species. The wasps have had that many generations to make the jump from one type of insect to another, from larvae to crickets to spiders, and they can lay 100ds of eggs. The specifics are very complicated, i don't know, here are some docs:  https://www.annualreviews.org/doi/10.1146/annurev.ento.51.110104.151029 and https://www.sciencedirect.com/science/article/abs/pii/S0065308X03540027?via%3Dihub

Context is everything. Lets start by working back to front.

larvae eat the tarantula organs in a specific sequence to keep it
  alive as long as possible.

Most of the time if the larva eat the organs in the wrong order they don't die, they just end up with less food. It is pretty easy to see how this could evolve to be better, larva that eat in the correct sequence end up with more food thus have an advantage, larva that eat in hte absolute wrong sequence don't survive.

on a [specific] species of tarantula

Again easy many wasps are not as picky they will lay their eggs in/on a wide variety of hosts, but specialization is favored a lot in evolution as it helps your lineage exploit a resource better and better, you only have to deal with the defenses of a single species as opposed to many different ones which might have mutually exclusive solutions.

lay their eggs in a specific region.

again failing to do this does not necessarily mean their larva die, it just means they are worse off becasue they don't get to eat as much. Again easy to see how this evolves, a wasp that picks its target end up with more well fed offspring. Many don't even lay their eggs inside the host but outside and let them eat the host from the outside in, this is what this species does.

Upon finding a tarantula, the wasp locks its mandibles onto a foreleg and brings its stinger into position so as to paralyze it.

Again not every parasitic wasp does this many don't paralyse their host, but they jab them with the ovipositor relying in brute force to injure, paralyse, or kill the host. Others just lay their eggs on them and fly away. Others simply kill the host jam it in a hole and lay their eggs on it. But wasps that paralyse the host are less likely to get attacked. but even if they kill the host instead the larva still get a meal. hunting always tends to be risky, but as long as the reward outweighs the risk it can evolve. Additionally many wasps do not target adults but larva and eggs that can't fight back. venomous Stinging is actually fairly rare in wasps occuring only in the ones that attack the most dangerous hosts. Of course once a wasp lineage gets good ant not killing its host then there is little reason for the larva to be able to eat more putrid remains of the host, as such adaptations are costly so you can see how after they stop killing the prey the larva might lose the ability to keep eating dead hosts.

The wasp then drags the tarantula into a hole that it has already dug.

Again not every species does this, some just lay their eggs on a host, without doing anything else, but this carries more risk of your larva getting dislodged or injured, but insects are not people if there is a parasite on their back there is not a lot they can do about it.

These wasps are solitary, which means there are no conspecifics to
  teach the new wasp how to do all this. Thus, the entire behavioral
  program described above must be encoded in the wasp's genome.

Even your own source disagrees with this, it shows wasps get better at subduing the host the more often they do it, laying eggs in NOT a once in lifetime thing they may do it many many times, so not being perfect can still work.
Once you see the huge variety in parasitic wasp behavior it is much easier to the step by step sequence that can happen to get to each one. You are not even at the most extreme, there are wasps that go even further, like having viral mutualists, larva that can't poop so as not to contaminate a host they live inside, and even leaving chemical markers to keep other wasps from laying eggs in/on the same host. Parasitic wasps are rather well studied I invite you to look more into them, they are really good models of evolution.

parasitoid wasp evolution:
Started radiating about 127 million years ago, at the same time as Gymnosperms (flowering plants). Today they represent 10-20% of all insect species.
They have accompanied the other insect species in their diversification since that time, and often undergo co-speciation... When a host species divides into different types, the wasp species divides too.
Species that lay inside living insects are thought to be derived from wasps that lay eggs on or in other insect's eggs or pupae. Endoparasitoids have evolved from ectoparasitoids independently in different hymenopteran lineages.
Some species also lay microeggs on leaves near a larvae, and when the host eats the leaf and the egg, it develops inside them.
They have both a sting and an ovipositor, which permits different species a variety of specialized and opportunistic behaviours to lay on or inside eggs, and to inject genes and venoms which inject into the host to modulate host immunity, metabolism and development. Up to 70 different venom proteins have been found in a single wasp species.
Parasitoids can also inject substances like polydnaviruses (PDVs), virus-like particles (VLPs), ovarian fluids and teratocytes.
This kindof reflects the complex evolution of the Pepsis species described... The different components of venoms and behaviours came as little changes over 100ds of millions of years, and the specialization on a single species of tarantula kindof gives the wasp exclusivity from intra clade competition.
Digging a hole to put the spider in does seem overly complex. apparently, it must have first learnt to pull the animal into a hidden recess... Afterwards it started to scratch and clear the recess, and that foraging movement eventually turned into excavation of a pit prior to dragging the prey.
here's one of the most readable references: https://www.nature.com/articles/srep19604


text:
Sense and anti sense strand
Why the sense strand is only involved in transcription though the antisense strand just has the compliment strand of the sense strand?

I don't understand your question. The sense (coding) and antisense (template) strands are defined by which strand is transcribed.

Is there anything that always a particular strand is transcribed

I mean when the sense strand is being transcribed for one gene why can't the antisense strand can be transcribed simultaneously for another gene as both strands contain the same genetic material

Which strand is transcribed depends on the gene. The terms sense and antisense are only useful when talking about a single gene. Between genes on a chromosome, a DNA strand may be sense for one gene and antisense for another.

This paper presents an interesting idea that the 2 classes of amino acyl tRNA synthetases originated as 2 genes on opposite strands of a double-stranded RNA. This would be helpful in a primitive mostly-RNA world where making long RNAs would have been hard and overlapping the genes would save space.

The short answer is the transcription machinery will only bind on the correct orientation.  The binding of proteins and such to the promoter DNA strand is determined by the sequence of the DNA, the sequence is not correct on the anti-sense strand for a given gene.

Either strand of DNA can be sense or antisense.  SWBarnes2 posts that the "transcription machinery will only bind on the correct orientation" and that is indeed what determines which strand is sense.  But note his important statement "the sequence is not correct on the anti-sense strand FOR A GIVEN GENE" (my emphasis).  As you move from gene to gene, the sense strand can swap strands.  Coding sequences can overlap running in opposite directions, making both strands sense; this is more commonly a viral trick.  Sense and antisense are defined by what sequence is found in RNA and so the map of sense and antisense strands on DNA is complicated. As you move along a strand of DNA one strand might be sense, then the other, then both, then neither.

One of the reasons why DNA is double stranded--this means DNA has sense and antisense strands--is to make a copy.
During transcription, RNAs are transcribed referring to anti-sense strand sequences--making base pairs with anti-sense strand. In other words, the sense strand does not do anything during transcription.