Recent human evolution

Recent human evolution refers to evolutionary <a href="/facts/Adaptation/5K2gNpDB">adaptation</a>, <a href="/facts/Sexual_selection/AjDd8Tam">sexual</a> and <a href="/facts/Natural_selection/JXTte6en">natural selection</a>, and <a href="/facts/Genetic_drift/lvoEEctX">genetic drift</a> within <a href="/facts/Human/rlcTENsr">Homo sapiens</a> populations, since their separation and dispersal in the <a href="/facts/Middle_Paleolithic/NlQRStWY">Middle Paleolithic</a> about 50,000 years ago. Contrary to popular belief, not only are humans still evolving, their evolution since the dawn of agriculture is faster than ever before. It has been proposed that human culture acts as a selective force in human evolution and has accelerated it; however, this is disputed. With a sufficiently large data set and modern research methods, scientists can study the changes in the <a href="/facts/Allele_frequency/gRApYaIy">frequency of an allele</a> occurring in a tiny subset of the population over a single lifetime, the shortest meaningful time scale in evolution. Comparing a given gene with that of other species enables geneticists to determine whether it is rapidly evolving in humans alone. For example, while human DNA is on average 98% identical to chimp DNA, the so-called Human Accelerated Region 1 (<a href="/facts/Human_accelerated_region_1/Hg9Ifnxw">HAR1</a>), involved in the development of the <a href="/facts/Human_brain/qfSwSB8K">brain</a>, is only 85% similar.
Following the <a href="/facts/Early_human_migrations/9df1IjAy">peopling of Africa</a> some 130,000 years ago, and the <a href="/facts/Coastal_migration/lz05ehU2">recent Out-of-Africa</a> expansion some 70,000 to 50,000 years ago, some sub-populations of Homo sapiens have been geographically isolated for tens of thousands of years prior to the early modern <a href="/facts/Age_of_Discovery/Hy29CbgV">Age of Discovery</a>. Combined with archaic admixture, this has resulted in relatively significant <a href="/facts/Human_genetic_variation/bgU0WXSf">genetic variation</a>. Selection pressures were especially severe for populations affected by the <a href="/facts/Last_Glacial_Maximum/BXQyc9IP">Last Glacial Maximum</a> (LGM) in Eurasia, and for <a href="/facts/Sedentism/5lUa65CJ">sedentary</a> <a href="/facts/Neolithic_Revolution/P5tLdcgU">farming</a> populations since the <a href="/facts/Neolithic/wRS0Bnh4">Neolithic</a>, or New Stone Age.
<a href="/facts/Single-nucleotide_polymorphism/Qy5Y2wom">Single nucleotide polymorphisms</a> (SNP, pronounced 'snip'), or mutations of a single genetic code "letter" in an allele that spread across a population, in functional parts of the genome can potentially modify virtually any conceivable trait, from height and eye color to susceptibility to diabetes and schizophrenia. Approximately 2% of the human genome codes for proteins and a slightly larger fraction is involved in gene regulation. But most of the rest of the genome has no known function. If the environment remains stable, the beneficial mutations will spread throughout the local population over many generations until it becomes a dominant trait. An extremely beneficial allele could become ubiquitous in a population in as little as a few centuries whereas those that are less advantageous typically take millennia.
Human traits that emerged recently include the ability to <a href="/facts/Freediving/PxMgkHp3">free-dive</a> for long periods of time, <a href="/facts/High-altitude_adaptation_in_humans/kfeBPYrc">adaptations for living in high altitudes</a> where oxygen concentrations are low, resistance to <a href="/facts/Infection/182XrncP">contagious diseases</a> (such as <a href="/facts/Malaria/rN3g58CX">malaria</a>), <a href="/facts/Light_skin/bM6tDwNf">light skin</a>, <a href="/facts/Eye_color/50sYzD22">blue eyes</a>, <a href="/facts/Lactase_persistence/xo4m5guz">lactase persistence</a> (or the ability to digest milk after weaning), lower blood pressure and <a href="/facts/Cholesterol/TnfPlYc1">cholesterol levels</a>, retention of the median artery, reduced prevalence of <a href="/facts/Alzheimer%27s_disease/w7Ad6tdg">Alzheimer's disease</a>, lower susceptibility to <a href="/facts/Diabetes/2xeHXbsI">diabetes</a>, genetic longevity, shrinking <a href="/facts/Brain_size/K0xy5XT5">brain sizes</a>, and changes in the timing of <a href="/facts/Menarche/EFzGSWMk">menarche</a> and <a href="/facts/Menopause/b3Fz6NHb">menopause</a>.

Recent human evolution open-in-new

Recent human evolution