an organism's genes come from the nuclear genome.
where do an organism’s genes come from?
nuclear genome
genes come in pairs; one from the mother and one from the father. a carrier is a person who inherited one abnormal gene from one of their parents. carriers often show no symptoms of the genetic disorder that they carry an abnormal gene for. usually the only time a person finds out that they are a carrier for a specific genetic disorder is when they have an affected child. for these kinds of genetic diseases to be present in a person, two copies of the abnormal gene are needed. this means that both of the parents have to be a carrier for the child to inherit the disease.
carrier testing
how did evolutionary non-related genes come in close proximity in the first place? either there is a force that brings functionally related genes near to each other, or the genes came near by change. singer et al. proposed that genes came in close proximity by random recombination of genome segments. when functionally related genes came in close proximity to each other, this proximity was conserved. they determined all possible recombination sites between genes of human and mouse. after that, they compared the clustering of the mouse and human genome and looked if recombination had occurred at the potentially recombination sites. it turned out that recombination between genes of the same cluster was very rare. so, as soon as a functional cluster is formed recombination is suppressed by the cell. on sex chromosomes, the amount of clusters is very low in both human and mouse. the authors reasoned this was due to the low rate of chromosomal rearrangements of sex chromosomes.
ridge (biology)