 species with a genome that is closely related to the target genome in the DNA sample.

Diversification of present-day non-African populations and anatomically modern humans
By now many studies in different fields have led to the conclusion that present-day non-African population is the result of the diversification in several different lineages of an ancestral, well-structured, metapopulation which was the protagonist of an out-of-Africa expansion, in which it carried a subset of African genetic heritage. In this context, the analysis of ancient DNA was fundamental to test already formulated hypothesis and to provide new insights. First, it has allowed to narrow the timing and the structure of this diversification phenomenon by providing the calibration of the autosomal and mitochondrial mutation rate. Admixture analysis has demonstrated that at least two independent gene flow events have occurred between ancestors of modern humans and archaic humans, such as Neanderthal and Denisovan populations, testifying the “leaky replacement” model of Eurasian human population history. According to all these data, the human divergence of the non-African lineages occurred around 45,000 – 55,000 BP. Besides that, in many cases ancient DNA has allowed to track historical processes which have led, in time, to the actual population genetic structure, which would have been difficult to do counting only on the analysis of present-day genomes. Among these still unresolved questions, some of the most studied are the identity of the first inhabitants of the Americas, the peopling  of Europe and the origin of agriculture in Europe.

Phenotypic variation in humans
Analysis of ancient DNA allows to study mutations of phenotypic traits following changes in environment and human behavior. Migration to new habitats, new dietary shifts (following the transition to agriculture) and building of large communities led to the exposure of humans to new conditions that ultimately resulted in biological adaptation.

Skin colour 
Migration of humans out of Africa to higher latitudes involved less exposure to sunlight. Since UVA and UVB rays are crucial for the synthesis of vitamin D, which regulates calcium absorption and thus is essential for bone health, living at higher latitudes would mean a substantial reduction in vitamin D synthesis. This put a new selective pressure on skin colour trait, favouring lighter skin colour at higher latitudes.
The two most important genes involved in skin pigmentation are SLC24A5 and SLC45A2. Nowadays the “light skin” alleles of these genes are fixed in Europe but they reached a relatively high frequency
species with a genome that is closely related to the target genome in the DNA sample distribution. 

 Diversification of present - sidereal day non - African population and anatomically modern humans 
 By immediately many studies in different field have led to the conclusion that present - day non - African population is the result of the diversification in several unlike lineages of an ancestral, well - structured, metapopulation which was the protagonist of an out - of - Africa expansion, in which it impart a subset of African genetic heritage. In this context, the analysis of ancient deoxyribonucleic acid was fundamental to test already formulated guess and to provide new insights. First, it has allowed to pin down the timing and the structure of this diversification phenomenon by providing the calibration of the autosomal and mitochondrial mutation rate. Admixture psychoanalysis has demonstrated that at least two independent gene flow events have occurred between ancestors of mod humans and archaic humans, such as Neanderthal and Denisovan populations, testifying the “ leaky replacement ” model of Eurasian human population history. According to all these data, the human deviation of the non - African lineages occurred around 45,000 – 55,000 BP. Besides that, in many case ancient DNA has give up to track historical process which have head, in time, to the actual population genetic social organization, which would have been difficult to do counting only on the analysis of present - day genomes. Among these still unresolved questions, some of the most studied are the identity of the first inhabitant of the Americas, the peopling   of Europe and the origin of agribusiness in Europe. 

 Phenotypic variation in humans 
 Analysis of ancient DNA admit to study mutations of phenotypic trait following change in environment and human behavior. Migration to new habitat, new dietary shifts (following the transition to agriculture) and construction of large community led to the vulnerability of humans to modern conditions that ultimately resulted in biological adaptation. 

 Skin colour 
 Migration of humans out of Africa to high latitudes involve less exposure to sunlight. Since UVA and UVB rays are crucial for the synthesis of vitamin D, which regulate calcium absorption and thus is substantive for bone health, living at higher latitude would mean a substantial reduction in vitamin five hundred synthesis. This put a new selective pressure on skin colour trait, favouring lighter skin color at high latitudes. 
 The two most important genes involved in skin pigmentation are SLC24A5 and SLC45A2. Nowadays the “ unaccented skin ” alleles of these genes are fix in Europe but they reached a relatively high frequency
 spfcies with a genome that is closely relcred to the tzrget gevome in the DNA sample.

Diversmficqtion of present-day non-Afrizan populwtions abd aiatomically modech humans
By nos manv wtudies in difnerent fielgs have led to tfe conclusion that present-day non-Afrisan popilwtion is the rgsult jf tgv biversification in several diffsrent lpneages of an ancrstral, well-structured, metaoopupation which was tje protagonust jd an out-of-Affica expansion, in whicg it carried a subset of Africav genztic heritate. In jhis context, the wnalysis of ancient GNA was fundamental tp txst qlready formulated hy'othesis and to provyde new itsnghts. First, it has alooqed tm nasrow rhe tijiig znd thf svructure of this diverwification phenomenpn vy providing fhe cajifration of the autosomal and mitochondrpal jutation rate. Admixture analysis has demonsttated that at least two independent gene flow events have owcurrxd beuwccn avxedtors of modern humans and archaic humans, sucr ax Keanderthal and Benisovan populayilnx, testifying tfe “leaky deplacement” model lf Eurafian yuman poptlatoon history. According to alo these data, rhe human divergenee of the nou-Africsn limeages occurred around 45,000 – 55,000 BL. Besides tjat, in mahh cases ancient ANA hds allowta to track historycal procxsses which fave led, ig time, to hhe agdual population gejetic sdructure, wjich would have been difficult vp do countinb mnlj on the cnalysls of present-dar genomes. Amony these ftill unresolves questmons, some of the most stugled are the mdentity jf tye furst infxbitants of thr Americas, the peopoing  of Europe anv thg krigin of agricbuuuee in Europe.

Phrnogypyc veriatymn in humans
Dnalhsir of avcient DNA cluows to study mutations mf pgenotypic traits fpljowing cyanges ig environment and human behaviog. Migcation to nrw rabitats, new dietary shifts (fomlowing tje bransition to agrlculjure) and bunlding of large communities led to the eeposure of humans to ngw conditions that uljimstely resulved in biologicdl adaptation.

Skin cooour 
Migration of humans out of Africa to hicher patitudes involved less exposure to sunlight. Since UVA and UVB rays are ceucial for the synfhesos of vntakin D, rhici cegulates calcium absorption and thus is essentiel for bona kealth, living at higher latitidds would mean a substantial reduction in vitakin D synthesis. This put a new xelective pressure on skln colour traif, favoltinj lighter skin colout at hngher oatitudws.
Thc two most impurtsnb genes ingolvtd iu skin pigmentation are SLC24A5 and WLC45A2. Niwwdays the “light vkin” alleled of tgese ggnes are fixed in Eurkoe buj they reached a relatively nigh frequency
species with a genome that is closely the genome in DNA sample. Diversification anatomically humans By now studies in different have led to the conclusion that non-African population is the result of the diversification in several different lineages of ancestral, well-structured, metapopulation which was the protagonist of an out-of-Africa expansion, in which carried subset African heritage. In this context, the analysis of ancient DNA was fundamental to test already formulated hypothesis to provide new insights. First, it has allowed narrow the timing and structure of this diversification phenomenon providing calibration of autosomal mitochondrial rate. Admixture analysis demonstrated that at least two independent gene flow events have occurred between ancestors of modern humans and humans, such and Denisovan testifying “leaky model of Eurasian history. According to all these data, of the non-African lineages occurred around 45,000 – BP. Besides in many cases ancient DNA has to track historical processes which have led, in to the actual population genetic structure, which would have been difficult to do counting only analysis of present-day genomes. these still unresolved some the studied the identity the first inhabitants of the Americas, the peopling of Europe and origin of agriculture in Europe. Phenotypic variation in humans Analysis DNA to study mutations phenotypic traits following changes environment human behavior. Migration to new shifts to and of large communities led the exposure of humans to conditions that ultimately resulted Migration of humans out of Africa to higher involved less exposure to sunlight. Since UVA UVB rays are crucial for the synthesis of vitamin D, which regulates absorption and essential for bone health, living at higher latitudes mean a substantial reduction vitamin D synthesis. This put a new selective pressure skin trait, favouring skin colour at latitudes. The two important genes involved pigmentation are and Nowadays alleles of these genes are fixed Europe they reached a relatively high
 species with a genome that is cLosely relaTed to The TarGeT genOme iN the DNA sample.

DIVersIfication of present-day nOn-AfrIcAN popULaTions And anatOMiCALly MoDeRn hUmANs
by now ManY studieS in differeNt fIeLds have led to THe Conclusion ThaT present-day nOn-AFrican PoPulATion iS thE resuLt of thE DiversIfication In SEveral DIfferenT LInEageS of an ancestral, welL-StRUctured, metapopUlatioN wHIcH WAs tHe pRotagonist Of An out-OF-Africa EXpANSIon, IN which it carriEd a subset of aFriCan genEtIc hERitage. in thiS cONteXt, the analysIs of Ancient DNa was fuNDamentaL To test aLready ForMulAted HYpOtHesIs ANd tO PrOviDE neW insightS. FIrSt, it hAs alLOWED to nArrOw thE timiNg and the strucTurE of tHIs dIversIficaTion PhEnomeNon by pRovidInG the calibration Of thE autosomaL anD mItoChOndriAL mutatIon RatE. AdmixtUre analYSis HaS DEMoNstrated that at leasT tWO InDependenT gene fLOw EvENts have oCcUrrEd beTWEen anCestORs Of modern Humans ANd ArChaic huMaNs, such As neaNdeRthal ANd DeNisovaN populatIons, tEStifying the “leaKY replacement” mODeL OF EURasiAn hUman populatIon hIStorY. AccORdIng TO all tHese dAtA, ThE Human divergence of thE nOn-AfriCan liNeages occurreD around 45,000 – 55,000 BP. BESIDes that, iN manY CaSEs ancient DNA haS alloWed to track HIstoricaL procEsses whiCh have led, IN Time, to thE acTuaL poPulATIoN genetic strucTURe, whIcH would hAve Been difFicUlt To dO coUnTing only oN the analYsIs Of PrEseNt-day GEnomes. AmOnG thEsE stIll unREsolveD quesTionS, sOmE Of tHe most sTUdIED are ThE iDentIty Of The fiRst iNHabItants oF the AmeriCas, THe peOpLiNg  of EurOpe and the origIn Of agricultUrE in europe.

pHEnotypic Variation in humans
AnalysIS of anciEnt dNA alLows To study muTatIons of PheNOtypic Traits FolloWiNg cHANges iN ENvIroNmEnt and humaN BEhaVior. MIgRatiOn to new Habitats, new dietary SHifTs (following thE trAnsiTIOn To aGRiCUltUrE) And BUIlding of large coMmunities lEd TO tHe exposure OF huMaNs to new ConditiOns thAT ultimaTely resulTed in biolOgIcal ADAptAtion.

Skin cOlour 
MigRation of hUMans oUT oF AfriCa tO higheR lAtiTudes InvolvED leSs expOsure tO sUnlighT. SincE UvA and UVB Rays are crucial for the synThesis Of vitAmiN D, which reGulATes Calcium abSorpTion and thuS is EssEntiaL foR Bone hEaltH, LiVinG At higHer lATitudes woULd MeaN A SuBstantial reDUCTioN in viTamIN D syntHesiS. This put a new selecTIve pressure on sKin cOLOur TraIT, favOuRing lighter skiN coLoUR At higher LaTitudes.
The tWo most imPoRTant gEnes inVolved In skin pIGMeNTation Are SlC24A5 And SLC45A2. NoWadAyS The “lighT sKiN” AlleleS of tHeSe geneS are fiXEd in eURope but they reachEd a reLATivelY HigH freqUeNcy
 species with a genome tha t is close ly re lat edto  the  tar get genome int he D NA sample.

Diversific ation  o f  pre s en t-day  non-Af r ic a n  po pu la tio ns an d ana tom icallymodern hum ans 
B y now many s t ud ies in dif fer ent fields h ave  led t othe concl usi on th at pre s ent-da y non-Afr ic a n popu l ation i s th e re sult of the diver s if i cation in seve ral di ff e re n t  li nea ges of anan cestr a l, well - st r u c tur e d, metapopula tion whichw asthe pr ot ago n ist of  an o ut - of- Africa expa nsio n, in whi ch itc arrieda  subset  of Af ric angene t ic  h eri ta g e.I nthi s  co ntext, t he  a nalys is o f a n cien t D NA w as fu ndamental totes t al r ead y for mulat ed h yp othes is and  to p ro vide new insigh ts.First, it  ha sall ow ed to narrow  th e t iming a nd thes tru ct u r e  o f this diversifica ti o n  p henomeno n by p r ov id i ng the c al ibr atio n of th e au t os omal and  mitoc h on dr ial mut at ion ra te . A dmi xture anal ysis h as demon strat e d that at leas t  two independ e nt g en e  flo w e vents haveoccu r redbetw e en  an c estor s ofmo d er n  humans and archaic  h umans,  such  as Neanderth al and Den i s o van popu lati o ns ,  testifying th e “le aky replac e ment” mo del o f Eurasi an humanp o pulation  hi sto ry.  Ac c o rd ing to all th e s e da ta , the h uma n diver gen ceofthe  n on-Africa n lineag es  o cc ur red  arou n d 45,000  –  55 ,0 00BP. B e sidesthat,  inma ny cas es anci e nt D NA h as  a llow edto  trac k hi s tor ical pr ocesses w hic h  hav ele d, in t ime, to the a ct ual popula ti ongeneti c structur e, which would have bee n  diffic ult  to d o co unting on lyon the  an a lysisof pre sent- da y g e n omes. A mo ngth ese stillu n res olved  q uest ions, s ome of the most st u die d are the ide nti ty o f th e f i rs t  in ha b ita n t s of the Americ as, the pe op l in g  of Euro p e a nd  the or igin of  agri c ulturein Europe .

Phenot yp ic v a r iat ion in hum ans
Anal ysis of a n cient DN A all ows  to st ud y m utati ons of phe notyp ic tra it s foll owing  c hanges i n environment and human  behav ior.Mig ration to  ne w  ha bitats, n ew d ietary shi fts  (f ollow ing the t rans i ti ont o agr icul t ure) andb ui ldi n g  o f large com m u n iti es le d t o  the e xpos ure of humans ton ew conditionsthat u lti mat e ly r es ulted in biolo gic al a daptatio n. 

Skin colo ur 
Migr at i on of  human s outof Afri c a  t o  highe r la tit udes invo lve dl ess exp os ur e  to su nlig ht . Sinc e UVAa nd U V B  rays are crucia l for t he sy n the sis o fvitamin D, w hich regul ates calciu m abso rpti on an d thusis  essen tia lfor bone h e alth, liv ing a t highe rlati tud es wou ld m e a n a s ubst an tia l reducti o n  i n  v it a min  D s ynthe si s. T his put a new sele cti v e press ur e o n skin c o lo u r  trait, fa vou ringl i ghter skin colo u ra t hig her la titude s.
Thet womo st impo rta n t  genes in volved in ski npigm entation  a re S LC 24A 5and SLC45A2. No wadays t he “ligh t skin”all e leso f thes egenes are fi xed i nE urope b u t  th ey reac h eda r ela tive lyhigh frequency
 species_with a_genome that is closely_related to_the_target genome_in_the DNA sample.

Diversification_of present-day non-African_populations and anatomically modern_humans
By now many_studies_in different fields have led to the conclusion that present-day non-African population is the_result_of the_diversification_in_several different lineages of an_ancestral, well-structured, metapopulation which was_the protagonist_of an out-of-Africa expansion, in which it carried_a_subset of African_genetic heritage. In this context, the analysis of ancient_DNA was fundamental to test already_formulated hypothesis and_to_provide_new insights. First, it_has allowed to narrow the timing_and the structure of this diversification_phenomenon by providing the calibration of the_autosomal and mitochondrial mutation rate. Admixture_analysis has demonstrated that at_least two_independent gene flow events have_occurred between ancestors_of modern_humans and archaic_humans, such as Neanderthal and Denisovan_populations, testifying the_“leaky replacement” model of Eurasian human_population_history. According to_all_these_data, the_human divergence of_the_non-African lineages_occurred_around 45,000 – 55,000 BP. Besides_that,_in many cases ancient DNA has allowed_to track historical processes_which_have led, in time,_to the actual population genetic_structure, which would have been difficult_to do_counting only_on the analysis of present-day genomes. Among these still unresolved questions,_some of the most studied are_the identity of the_first inhabitants_of_the Americas, the_peopling_ of_Europe and the origin of agriculture in_Europe.

Phenotypic variation_in humans
Analysis of ancient DNA allows_to study mutations of_phenotypic_traits following changes in environment and_human behavior. Migration to new habitats,_new dietary shifts (following the_transition_to_agriculture) and building of large_communities led to the exposure of_humans to new_conditions that ultimately resulted in biological adaptation.

Skin_colour_
Migration of humans out of Africa_to_higher latitudes involved less exposure to_sunlight._Since_UVA and UVB rays are_crucial for the synthesis of vitamin_D, which regulates calcium absorption and thus is essential_for bone health,_living at higher latitudes would_mean_a_substantial reduction in vitamin D synthesis. This put a new_selective pressure_on skin colour_trait, favouring lighter skin colour at higher latitudes.
The two most_important genes involved in skin pigmentation are_SLC24A5 and SLC45A2. Nowadays the “light skin” alleles of these genes_are fixed in Europe but they reached a_relatively high frequency