Editing Human evolution (section)

== Recent and ongoing human evolution ==
{{Main|Recent human evolution}}
[[Anatomically modern human]] populations continue to evolve, as they are affected by both natural selection and [[genetic drift]]. Although [[selection pressure]] on some traits, such as resistance to smallpox, has decreased in the modern age, humans are still undergoing natural selection for many other traits. Some of these are due to specific environmental pressures, while others are related to lifestyle changes since the development of agriculture (10,000 years ago), urbanization (5,000), and industrialization (250 years ago). It has been argued that human evolution has accelerated since the development of agriculture 10,000 years ago and civilization some 5,000 years ago, resulting, it is claimed, in substantial genetic differences between different current human populations,{{sfn|Cochran|Harpending|2009}} and more recent research indicates that for some traits, the developments and innovations of human culture have driven a new form of selection that coexists with, and in some cases has largely replaced, natural selection.<ref>{{Cite journal |last=Bender |first=Andrea |date=August 8, 2019 |title=The Role of Culture and Evolution for Human Cognition |journal=Topics in Cognitive Science |volume=12 |issue=4 |pages=1403–1420 |doi=10.1111/tops.12449 |pmid=31392845 |issn=1756-8757 |doi-access=free |hdl=1956/22031 |hdl-access=free}}</ref>

[[File:Homo sapiens sapiens, Oase, Rumänien (Daniela Hitzemann).jpg|thumb|180px|Reconstruction of the [[Initial Upper Paleolithic|upper Palaeolithic]] human [[Oase 2]] {{c.|40 000 years BP}}<ref>{{cite journal |last1=Fu |first1=Q. |last2=Hajdinjak |first2=M. |last3=Moldovan |first3=O. T. |last4=Constantin |first4=S. |last5=Mallick |first5=S. |last6=Skoglund |first6=Pontus |last7=Patterson |first7=N. |last8=Rohland |first8=N. |last9=Lazaridis |first9=I. |last10=Nickel |first10=B. |last11=Viola |first11=B. |last12=Prüfer |first12=Kay |last13=Meyer |first13=M. |last14=Kelso |first14=J. |last15=Reich |first15=D. |last16=Pääbo |first16=S. |author16-link=Svante Pääbo |title=An early modern human from Romania with a recent Neanderthal ancestor |journal=[[Nature (journal)|Nature]] |date=2015 |volume=524 |issue=7564 |pages=216–219 |doi=10.1038/nature14558 |pmid=26098372 |pmc=4537386 |bibcode=2015Natur.524..216F}}</ref>]]
Particularly conspicuous is variation in superficial characteristics, such as [[Afro-textured hair]], or the recent evolution of [[light skin]] and blond hair in some populations, which are attributed to differences in climate. Particularly strong selective pressures have resulted in [[high-altitude adaptation in humans]], with different ones in different isolated populations. Studies of the [[High-altitude adaptation in humans#Genetic basis|genetic basis]] show that some developed very recently, with Tibetans evolving over 3,000 years to have high proportions of an allele of [[EPAS1]] that is adaptive to high altitudes.

Other evolution is related to [[endemic disease]]s: the presence of [[malaria]] selects for [[sickle cell trait]] (the [[heterozygous]] form of sickle cell gene), while in the absence of malaria, the health effects of [[sickle-cell anemia]] select against this trait. For another example, the population at risk of the severe debilitating disease [[kuru (disease)|kuru]] has significant over-representation of an immune variant of the [[PRNP|prion protein]] gene G127V versus non-immune alleles. The frequency of this [[Mutation|genetic variant]] is due to the survival of immune persons.<ref>{{cite news |author=Medical Research Council [UK] |author-link=Medical Research Council (United Kingdom) |date=November 21, 2009 |title=Brain Disease 'Resistance Gene' evolves in Papua New Guinea community; could offer insights into CJD |url= https://www.sciencedaily.com/releases/2009/11/091120091959.htm |work=ScienceDaily |access-date=November 22, 2009 |archive-date=June 8, 2019 |archive-url= https://web.archive.org/web/20190608194846/https://www.sciencedaily.com/releases/2009/11/091120091959.htm |url-status=live}}</ref><ref>{{Cite journal |doi=10.1056/NEJMoa0809716 |pmid=19923577 |date=2009 |display-authors=3 |last1=Mead |first1=S. |last2=Whitfield |first2=J. |last3=Poulter |first3=M. |last4=Shah |first4=P. |last5=Uphill |first5=J. |last6=Campbell |first6=T. |last7=Al-Dujaily |first7=H. |last8=Hummerich |first8=H. |last9=Beck |first9=J. |last10=Mein |first10=C. A. |last11=Verzilli |first11=C. |last12=Whittaker |first12=J. |last13=Alpers |first13=M. P. |last14=Collinge |first14=J. |title=A Novel Protective Prion Protein Variant that Colocalizes with Kuru Exposure |volume=361 |issue=21 |pages=2056–2065 |journal=The New England Journal of Medicine |url= https://researchonline.lshtm.ac.uk/4514/1/nejmoa0809716.pdf |access-date=August 20, 2019 |archive-date=July 20, 2018 |archive-url= https://web.archive.org/web/20180720215808/http://researchonline.lshtm.ac.uk/4514/1/nejmoa0809716.pdf |url-status=live}}{{collapsible list |title=Full list of authors |bullets=true |Simon Mead |Jerome Whitfield |Mark Poulter |Paresh Shah |James Uphill |Tracy Campbell |Huda Al-Dujaily |Holger Hummerich |Jon Beck |Charles A. Mein |Claudio Verzilli |John Whittaker |Michael P. Alpers |John Collinge}}</ref> Some reported trends remain unexplained and the subject of ongoing research in the novel field of evolutionary medicine: [[polycystic ovary syndrome]] (PCOS) reduces fertility and thus is expected to be subject to extremely strong negative selection, but its relative commonality in human populations suggests a counteracting selection pressure. The identity of that pressure remains the subject of some debate.<ref>{{Cite journal |last1=Corbett |first1=Stephen |last2=Morin-Papunen |first2=Laure |date=July 2013 |title=The Polycystic Ovary Syndrome and recent human evolution |journal=Molecular and Cellular Endocrinology |volume=373 |issue=1–2 |pages=39–50 |pmid=23352610 |s2cid=13078403 |doi=10.1016/j.mce.2013.01.001 |url= https://linkinghub.elsevier.com/retrieve/pii/S030372071300004X |access-date=October 8, 2020 |archive-date=May 25, 2021 |archive-url= https://web.archive.org/web/20210525180722/https://linkinghub.elsevier.com/retrieve/pii/S030372071300004X |url-status=live}}</ref>

Recent human evolution related to agriculture includes genetic resistance to infectious disease that has appeared in human populations by crossing the species barrier from domesticated animals,{{sfn|Diamond|1999}} as well as changes in metabolism due to changes in diet, such as [[lactase persistence]].

Culturally-driven evolution can defy the expectations of natural selection:  while human populations experience some pressure that drives a selection for producing children at younger ages, the advent of effective contraception, higher education, and changing social norms have driven the observed selection in the opposite direction.<ref>{{Cite journal |last1=Courtiol |first1=Alexandre |last2=Tropf |first2=Felix C. |last3=Mills |first3=Melinda C. |date=July 12, 2016 |title=When genes and environment disagree: Making sense of trends in recent human evolution |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=113 |issue=28 |pages=7693–7695 |doi=10.1073/pnas.1608532113 |issn=0027-8424 |pmc=4948334 |pmid=27402758 |bibcode=2016PNAS..113.7693C |doi-access=free}}</ref> However, culturally-driven selection need not necessarily work counter or in opposition to natural selection:  some proposals to explain the high rate of recent human brain expansion indicate a kind of feedback whereupon the brain's increased social learning efficiency encourages cultural developments that in turn encourage more efficiency, which drive more complex cultural developments that demand still-greater efficiency, and so forth.<ref>{{Cite journal |last1=Markov |first1=Alexander V. |last2=Markov |first2=Mikhail A. |date=June 2020 |title=Runaway brain-culture coevolution as a reason for larger brains: Exploring the "cultural drive" hypothesis by computer modeling |journal=Ecology and Evolution |volume=10 |issue=12 |pages=6059–6077 |doi=10.1002/ece3.6350 |issn=2045-7758 |pmc=7319167 |pmid=32607213 |bibcode=2020EcoEv..10.6059M}}</ref> Culturally-driven evolution has an advantage in that in addition to the genetic effects, it can be observed also in the archaeological record:  the development of stone tools across the Palaeolithic period connects to culturally-driven cognitive development in the form of skill acquisition supported by the culture and the development of increasingly complex technologies and the cognitive ability to elaborate them.<ref>{{Cite journal |last=Stout |first=Dietrich |date=April 12, 2011 |title=Stone toolmaking and the evolution of human culture and cognition |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=366 |issue=1567 |pages=1050–1059 |doi=10.1098/rstb.2010.0369 |issn=0962-8436 |pmc=3049103 |pmid=21357227}}</ref>

In contemporary times, since industrialization, some trends have been observed: for instance, menopause is evolving to occur later.<ref name="doi10.1073/pnas.0906199106" /> Other reported trends appear to include lengthening of the human reproductive period and reduction in cholesterol levels, blood glucose and blood pressure in some populations.<ref name="doi10.1073/pnas.0906199106">{{Cite journal |first1=S. G. |last1=Byars |last3=Govindaraju |first2=D. |first3=D. R. |last2=Ewbank |first4=S. C. |last4=Stearns |title=Natural selection in a contemporary human population |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |date=2009 |pmid=19858476 |pmc=2868295 |doi=10.1073/pnas.0906199106 |volume=107 |issue=suppl_1 |pages=1787–1792 |bibcode=2010PNAS..107.1787B |doi-access=free}}</ref>