Editing Human evolution (section)

=== Inter-species breeding ===
{{Further|Interbreeding between archaic and modern humans}}
[[File:Homo lineage 2017update.svg|thumb|upright=1.35|A model of the evolution of the genus ''Homo'' over the last 2&nbsp;million years (vertical axis). The rapid "[[Recent African origin of modern humans|Out of Africa]]" expansion of ''H. sapiens'' is indicated at the top of the diagram, with admixture indicated with [[Neanderthals]], [[Denisovans]], and unspecified archaic African hominins.]]
The hypothesis of interbreeding, also known as hybridization, admixture or hybrid-origin theory, has been discussed ever since the discovery of Neanderthal remains in the 19th century.<ref>{{cite book |last=Huxley |first=T. |title=Collected Essays: Volume VII, Man's Place in Nature |date=1890 |chapter=The Aryan Question and Pre-Historic Man |chapter-url= http://aleph0.clarku.edu/huxley/CE7/Aryan.html |access-date=August 25, 2018 |archive-date=July 26, 2011 |archive-url= https://web.archive.org/web/20110726231311/http://aleph0.clarku.edu/huxley/CE7/Aryan.html |url-status=live}}</ref> The linear view of human evolution began to be abandoned in the 1970s as different species of humans were discovered that made the linear concept increasingly unlikely. In the 21st century with the advent of molecular biology techniques and computerization, [[whole-genome sequencing]] of Neanderthal and human [[genome]] were performed, confirming recent admixture between different human species.<ref name="greenetal" /> In 2010, evidence based on molecular biology was published, revealing unambiguous examples of interbreeding between archaic and modern humans during the [[Middle Paleolithic]] and early [[Upper Paleolithic]]. It has been demonstrated that interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.<ref>{{cite web |last=Coghlan |first=Andy |date=March 15, 2018 |url= https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice/ |title=Our ancestors mated with the mystery 'Denisovan' people – twice |work=[[New Scientist]] |access-date=August 25, 2018 |url-status=live |archive-url= https://web.archive.org/web/20180805035916/https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice |archive-date=August 5, 2018}}</ref> Today, approximately 2% of DNA from all non-African populations (including Europeans, Asians, and [[Oceanians]]) is Neanderthal,<ref name="greenetal" /> with traces of Denisovan heritage.<ref name="NG-20180822">{{cite news |last=Wei-Haas |first=Maya |date=August 22, 2018 |title=Ancient Girl's Parents Were Two Different Human Species – Born 90,000 years ago, the child is the first direct evidence of interbreeding among Neanderthals and their cousins the Denisovans |work=National Geographic |url= https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |access-date=August 22, 2018 |archive-date=June 14, 2019 |archive-url= https://web.archive.org/web/20190614092015/https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |url-status=dead}}</ref> Also, 4–6% of modern [[Melanesians|Melanesian]] genetics are Denisovan.<ref name="NG-20180822" /> Comparisons of the human genome to the genomes of Neandertals, Denisovans and apes can help identify features that set modern humans apart from other hominin species. In a 2016 [[comparative genomics]] study, a Harvard Medical School/UCLA research team made a world map on the distribution and made some predictions about where Denisovan and Neanderthal genes may be impacting modern human biology.<ref>{{cite web |url= https://www.sciencedaily.com/releases/2016/03/160328133514.htm |author=Cell Press |author-link=Cell Press |title=A world map of Neanderthal and Denisovan ancestry in modern humans |date=March 28, 2016 |website=ScienceDaily |access-date=August 25, 2018 |archive-date=August 26, 2018 |archive-url= https://web.archive.org/web/20180826005214/https://www.sciencedaily.com/releases/2016/03/160328133514.htm |url-status=live}}</ref><ref>{{cite journal |last1=Sankararaman |first1=S. |last2=Mallick |first2=S. |last3=Patterson |first3=N. |last4=Reich |first4=D. |date=March 28, 2016 |title=The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans |journal=Current Biology |volume=26 |issue=9 |pages=1241–1247 |doi=10.1016/j.cub.2016.03.037 |pmid=27032491 |pmc=4864120 |bibcode=2016CBio...26.1241S}}</ref>

For example, comparative studies in the mid-2010s found several [[Phenotypic trait|traits]] related to neurological, immunological,<ref>{{cite web |publisher=American Association for the Advancement of Science |work=the Neandertal Genome |url= http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |title=Human-Neandertal Comparisons |date=2010 |archive-url= https://web.archive.org/web/20200528032345/http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |archive-date=May 28, 2020}}</ref> developmental, and metabolic phenotypes, that were developed by archaic humans to European and Asian environments and inherited to modern humans through admixture with local hominins.<ref>{{cite journal |last1=Dannemann |first1=M. |last2=Andrés |first2=A. M. |last3=Kelso |first3=J. |title=Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors |date=2016 |journal=[[American Journal of Human Genetics]] |volume=98 |issue=1 |pages=22–33 |doi=10.1016/j.ajhg.2015.11.015 |pmid=26748514 |pmc=4716682}}</ref><ref>{{cite journal |last1=Gittelman |first1=Rachel M. |last2=Schraiber |first2=Joshua G. |last3=Vernot |first3=Benjamin |last4=Mikacenic |first4=Carmen |last5=Wurfel |first5=Mark M. |last6=Akey |first6=Joshua M. |date=2016 |title=Archaic Hominin Admixture Facilitated Adaptation to Out-of-Africa Environments |journal=[[Current Biology]] |volume=26 |issue=24 |pages=3375–3382 |doi=10.1016/j.cub.2016.10.041 |pmid=27839976 |pmc=6764441 |bibcode=2016CBio...26.3375G}}</ref>

Although the narratives of human evolution are often contentious, several discoveries since 2010 show that human evolution should not be seen as a simple linear or branched progression, but a mix of related species.<ref name="pmid21179161" /><ref name="Denisovans & Neandertals" /><ref name="Human Hybrids" /><ref name="Mosaic humans, the hybrid species" /> In fact, genomic research has shown that hybridization between substantially diverged lineages is the rule, not the exception, in human evolution.<ref name="Ackermann 2015">{{cite journal |title=The Hybrid Origin of "Modern" Humans |first1=Rebecca |last1=Rogers Ackermann |first2=Alex |last2=Mackay |first3=Michael L. |last3=Arnold |journal=Evolutionary Biology |date=October 2015 |doi=10.1007/s11692-015-9348-1 |volume=43 |issue=1 |pages=1–11 |s2cid=14329491}}</ref> Furthermore, it is argued that hybridization was an essential creative force in the emergence of modern humans.<ref name="Ackermann 2015" />