Editing Human evolution (section)

=== Neanderthal and Denisovan ===
{{Main|Neanderthal|Denisovan}}
[[File:Homo sapiens neanderthalensis-Mr. N.jpg|thumb|upright|Reconstruction of an elderly Neanderthal man]]
''Homo neanderthalensis'', alternatively designated as ''Homo sapiens neanderthalensis'',<ref>{{cite journal |last=Harvati |first=Katerina |date=January 2003 |title=The Neanderthal taxonomic position: Models of intra- and inter-specific craniofacial variation |journal=Journal of Human Evolution |volume=44 |issue=1 |pages=107–132 |doi=10.1016/S0047-2484(02)00208-7 |issn=0047-2484 |pmid=12604307 |bibcode=2003JHumE..44..107H}}</ref> lived in Europe and Asia from 400,000<ref>{{Cite journal |last1=Herrera |first1=K. J. |last2=Somarelli |first2=J. A. |last3=Lowery |first3=R. K. |last4=Herrera |first4=R. J. |title=To what extent did Neanderthals and modern humans interact? |date=2009 |journal=Biological Reviews |volume=84 |issue=2 |pages=245–257 |doi=10.1111/j.1469-185X.2008.00071.x |pmid=19391204 |s2cid=25787484}}</ref> to about 28,000 years ago.<ref>{{cite journal |doi=10.1038/nature05195 |pmid=16971951 |title=Late survival of Neanderthals at the southernmost extreme of Europe |journal=[[Nature (journal)|Nature]] |volume=443 |issue=7113 |pages=850–853 |date=2006 |last1=Finlayson |first1=C. |last2=Giles Pacheco |first2=F. |last3=Rodríguez-Vidal |first3=J. |last4=Fa |first4=D. A. |last5=Gutiérrez López |first5=J. M. |last6=Santiago Pérez |first6=A. |last7=Finlayson |first7=G. |last8=Allué |first8=E. |last9=Baena Preysler |first9=J. |last10=Cáceres |first10=I. |last11=Carrión |first11=J. S. |last12=Fernández-Jalvo |first12=Y. |last13=Gleed-Owen |first13=C. P. |last14=Jiménez-Espejo |first14=F. J. |last15=López Martínez |first15=P. |last16=López Sáez |first16=J. A. |last17=Riquelme Cantal |first17=J. A. |last18=Sánchez Marco |first18=A. |last19=Giles Guzmán |first19=F. |last20=Brown |first20=K. |last21=Fuentes |first21=N. |last22=Valarino |first22=C. A. |last23=Villalpando |first23=A. |last24=Stringer |first24=C. B. |last25=Martínez Ruíz |first25=F. C. |last26=Sakamoto |first26=T. |display-authors=3 |bibcode=2006Natur.443..850F |hdl=10261/18685 |s2cid=4411186}}{{collapsible list |title=Full list of authors |bullets=true |Clive Finlayson |Francisco Giles Pacheco |Joaquín Rodríguez-Vidal |Darren A. Fa |José María Gutierrez López |Antonio Santiago Pérez |Geraldine Finlayson |Ethel Allue |Javier Baena Preysler |Isabel Cáceres |José S. Carrión |Yolanda Fernández-Jalvo |Christopher P. Gleed-Owen |Francisco J. Jimenez-Espejo |Pilar López Martínez |José Antonio López Sáez |José Antonio Riquelme Cantal |Antonio Sánchez Marco |Francisco Giles Guzman |Kimberly Brown |Noemí Fuentes |Claire A. Valarino |Antonio Villalpando |Christopher B. Stringer |Francisca Martinez Ruiz |Tatsuhiko Sakamoto}}</ref>
There are a number of clear anatomical differences between [[anatomically modern humans]] (AMH) and Neanderthal specimens, many relating to the superior Neanderthal adaptation to cold environments. Neanderthal [[surface to volume ratio]] was even lower than that among modern [[Inuit]] populations, indicating superior retention of body heat.

Neanderthals also had significantly larger brains, as shown from brain endocasts, casting doubt on their intellectual inferiority to modern humans. However, the higher body mass of Neanderthals may have required larger brain mass for body control.<ref name="dunbar">{{Cite journal |last1=Pearce |first1=Eiluned |last2=Stringer |first2=Chris |last3=Dunbar |first3=R. I. M. |date=2013 |title=New insights into differences in brain organization between Neanderthals and anatomically modern humans |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=280 |issue=1758 |page=20130168 |doi=10.1098/rspb.2013.0168 |pmc=3619466 |pmid=23486442}}</ref> Also, recent research by Pearce, [[Chris Stringer|Stringer]], and Dunbar has shown important differences in brain architecture. The larger size of the Neanderthal orbital chamber and [[occipital lobe]] suggests that they had a better visual acuity than modern humans, useful in the dimmer light of glacial Europe.

Neanderthals may have had less [[Dunbar's number|brain capacity available for social functions]]. Inferring social group size from endocranial volume (minus occipital lobe size) suggests that Neanderthal groups may have been limited to 120 individuals, compared to 144{{cn|date=January 2024}}<ref>{{Cite journal |last1=Bocquet-Appel |first1=Jean-Pierre |last2=Degioanni |first2=Anna |date=December 2013 |title=Neanderthal Demographic Estimates |url= https://www.journals.uchicago.edu/doi/full/10.1086/673725# |journal=The University of Chicago Press Journals |volume=54 |issue=S8 |pages=S202–S213 |doi=10.1086/673725}}</ref> possible relationships for modern humans. Larger social groups could imply that modern humans had less risk of inbreeding within their clan, trade over larger areas (confirmed in the distribution of stone tools), and faster spread of social and technological innovations. All these may have all contributed to modern ''Homo sapiens'' replacing Neanderthal populations by 28,000 BP.<ref name="dunbar" />

Earlier evidence from sequencing mitochondrial DNA suggested that no significant gene flow occurred between ''H. neanderthalensis'' and ''H. sapiens'', and that the two were separate species that shared a common ancestor about 660,000 years ago.<ref>{{cite journal |last1=Krings |first1=Matthias |last2=Stone |first2=Anne |last3=Schmitz |first3=Ralf W. |last4=Krainitzki |first4=Heike |last5=Stoneking |first5=Mark |last6=Pääbo |first6=Svante |date=July 11, 1997 |title=Neandertal DNA sequences and the origin of modern humans |journal=[[Cell (journal)|Cell]] |volume=90 |issue=1 |pages=19–30 |doi=10.1016/S0092-8674(00)80310-4 |issn=0092-8674 |pmid=9230299 |hdl=11858/00-001M-0000-0025-0960-8 |s2cid=13581775 |display-authors=3 |hdl-access=free}}</ref><ref>{{cite journal |last1=Green |first1=Richard E. |last2=Malaspinas |first2=Anna-Sapfo |last3=Krause |first3=Johannes |last4=Briggs |first4=Adrian W. |last5=Johnson |first5=Philip L.F. |last6=Uhler |first6=Caroline |last7=Meyer |first7=Matthias |last8=Good |first8=Jeffrey M. |last9=Maricic |first9=Tomislav |last10=Stenzel |first10=Udo |last11=Prüfer |first11=Kay |last12=Siebauer |first12=Michael |last13=Burbano |first13=Hernán A. |last14=Ronan |first14=Michael |last15=Rothberg |first15=Jonathan M. |last16=Egholm |first16=Michael |last17=Rudan |first17=Pavao |last18=Brajković |first18=Dejana |last19=Kućan |first19=Željko |last20=Gušić |first20=Ivan |last21=Wikström |first21=Mårten |last22=Laakkonen |first22=Liisa |last23=Kelso |first23=Janet |last24=Slatkin |first24=Montgomery |last25=Pääbo |first25=Svante |date=August 8, 2008 |title=A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing |journal=Cell |volume=134 |issue=3 |pages=416–426 |doi=10.1016/j.cell.2008.06.021 |issn=0092-8674 |pmc=2602844 |pmid=18692465 |display-authors=3}}</ref><ref>{{cite journal |last1=Serre |first1=David |last2=Langaney |first2=André |last3=Chech |first3=Mario |last4=Teschler-Nicola |last5=Paunovic |last6=Mennecier |last7=Hofreiter |last8=Possnert |last9=Pääbo |date=March 2004 |title=No Evidence of Neandertal mtDNA Contribution to Early Modern Humans |journal=PLOS Biology |volume=2 |issue=3 |page=e57 |doi=10.1371/journal.pbio.0020057 |issn=1545-7885 |pmc=368159 |pmid=15024415 |display-authors=3 |doi-access=free}}</ref> However, a sequencing of the Neanderthal genome in 2010 indicated that Neanderthals did indeed interbreed with anatomically modern humans c. 45,000-80,000 years ago, around the time modern humans migrated out from Africa, but before they dispersed throughout Europe, Asia and elsewhere.<ref name="neandersequence">{{cite news |last=Viegas |first=Jennifer |date=May 6, 2010 |title=Neanderthals, Humans Interbred, DNA Proves |url= http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |work=Discovery News |location=Silver Spring, Maryland |publisher=[[Discovery Communications]] |access-date=April 30, 2015 |archive-url= https://web.archive.org/web/20150508221757/http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |archive-date=May 8, 2015}}</ref> The genetic sequencing of a 40,000-year-old [[Peștera cu Oase|human skeleton from Romania]] showed that 11% of its genome was Neanderthal, implying the individual had a Neanderthal ancestor 4–6 generations previously,<ref>{{cite journal |last=Calloway |first=Ewan |title=Early European may have had Neanderthal great-great-grandparent |journal=[[Nature (journal)|Nature]] |date=May 13, 2015 |url= https://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |doi=10.1038/nature.2015.17534 |s2cid=181973496 |access-date=January 23, 2019 |archive-date=January 15, 2019 |archive-url= https://web.archive.org/web/20190115110342/http://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |url-status=live}}</ref> in addition to a contribution from earlier interbreeding in the Middle East. Though this interbred Romanian population seems not to have been ancestral to modern humans, the finding indicates that interbreeding happened repeatedly.<ref>{{cite news |last=Sample |first=Ian |title=My Neanderthal sex secret: Modern European's great-great grandparent link |newspaper=[[The Guardian]] |date=June 22, 2015 |access-date=July 27, 2018 |url= https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |archive-date=September 23, 2016 |archive-url= https://web.archive.org/web/20160923235758/https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |url-status=live}}</ref>

All modern non-African humans have about 1% to 4% (or 1.5% to 2.6% by more recent data) of their DNA derived from Neanderthals.<ref name="greenetal" /><ref name="neandersequence" /><ref name="A high-coverage Neandertal genome f" /> This finding is consistent with recent studies indicating that the divergence of some human alleles dates to one Ma, although this interpretation has been questioned.<ref>{{cite journal |last1=Gutiérrez |first1=Gabriel |last2=Sánchez |first2=Diego |last3=Marín |first3=Antonio |date=August 2002 |title=A Reanalysis of the Ancient Mitochondrial DNA Sequences Recovered from Neandertal Bones |journal=Molecular Biology and Evolution |volume=19 |issue=8 |pages=1359–1366 |doi=10.1093/oxfordjournals.molbev.a004197 |issn=0737-4038 |pmid=12140248 |doi-access=free}}</ref><ref>{{cite journal |last1=Hebsgaard |first1=M. B. |last2=Wiuf |first2=C. |last3=Gilbert |first3=M. T. |last4=Glenner |first4=H. |last5=Willerslev |first5=E. |date=January 2007 |title=Evaluating Neanderthal Genetics and Phylogeny |journal=Journal of Molecular Evolution |volume=64 |issue=1 |pages=50–60 |doi=10.1007/s00239-006-0017-y |issn=0022-2844 |pmid=17146600 |s2cid=2746487 |url= http://www.birc.au.dk/%7Ewiuf/journalWiuf/jMolEvol64.pdf |archive-url= https://wayback.archive-it.org/all/20110401041826/http://www.birc.au.dk/~wiuf/journalWiuf/jMolEvol64.pdf |archive-date=April 1, 2011 |access-date=October 24, 2017 |citeseerx=10.1.1.174.8969 |bibcode=2007JMolE..64...50H}}</ref> Neanderthals and AMH ''Homo sapiens'' could have co-existed in Europe for as long as 10,000 years, during which AMH populations exploded, vastly outnumbering Neanderthals, possibly outcompeting them by sheer numbers.<ref>{{cite journal |last1=Mellars |first1=Paul |last2=French |first2=Jennifer C. |date=July 29, 2011 |title=Tenfold Population Increase in Western Europe at the Neandertal–to–Modern Human Transition Paul |journal=[[Science (journal)|Science]] |volume=333 |issue=6042 |pages=623–627 |bibcode=2011Sci...333..623M |doi=10.1126/science.1206930 |issn=0036-8075 |pmid=21798948 |s2cid=28256970}}</ref>

In 2008, archaeologists working at the site of [[Denisova Cave]] in the [[Altai Mountains]] of [[Siberia]] uncovered a small bone fragment from the fifth finger of a juvenile member of another human species, the Denisovans.<ref>{{cite journal |last=Brown |first=Terence A. |date=April 8, 2010 |title=Human evolution: Stranger from Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=838–839 |bibcode=2010Natur.464..838B |doi=10.1038/464838a |issn=0028-0836 |pmid=20376137 |s2cid=4320406 |doi-access=free}}</ref> Artifacts, including a bracelet, excavated in the cave at the same level were [[Radiocarbon dating|carbon dated]] to around 40,000 BP. As DNA had survived in the fossil fragment due to the cool climate of the Denisova Cave, both mtDNA and nuclear DNA were sequenced.<ref name="pmid21179161" /><ref name="Pääbo et al.">{{cite journal |last1=Krause |first1=Johannes |author1-link=Johannes Krause |last2=Fu |first2=Qiaomei |last3=Good |first3=Jeffrey M. |last4=Viola |first4=Bence |last5=Shunkov |first5=Michael V. |last6=Derevianko |first6=Anatoli P. |last7=Pääbo |first7=Svante |author7-link=Svante Pääbo |display-authors=3 |date=April 8, 2010 |title=The complete mitochondrial DNA genome of an unknown hominin from southern Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=894–897 |bibcode=2010Natur.464..894K |doi=10.1038/nature08976 |issn=0028-0836 |pmid=20336068 |pmc=10152974 |s2cid=4415601 |doi-access=free}}</ref>

While the divergence point of the mtDNA was unexpectedly deep in time,<ref name="The Scientist">{{cite news |last=Katsnelson |first=Alla |date=March 24, 2010 |title=New hominin found via mtDNA |url= http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |work=The Nutshell |type=Blog |location=Philadelphia |publisher=[[The Scientist (magazine)|The Scientist]] |issn=0890-3670 |access-date=May 1, 2015 |archive-date=July 2, 2015 |archive-url= https://web.archive.org/web/20150702154449/http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |url-status=live}}</ref> the full genomic sequence suggested the Denisovans belonged to the same lineage as Neanderthals, with the two diverging shortly after their line split from the lineage that gave rise to modern humans.<ref name="pmid21179161" /> Modern humans are known to have overlapped with Neanderthals in Europe and the Near East for possibly more than 40,000 years,<ref>"Kaufman, Danial (2002), "Comparisons and the Case for Interaction among Neanderthals and Early Modern Humans in the Levant" (Oxford Journal of Anthropology)</ref> and the discovery raises the possibility that Neanderthals, Denisovans, and modern humans may have co-existed and interbred. The existence of this distant branch creates a much more complex picture of humankind during the [[Late Pleistocene]] than previously thought.<ref name="Pääbo et al." /><ref>{{cite journal |last1=Bokma |first1=Folmer |last2=van den Brink |first2=Valentijn |last3=Stadler |first3=Tanja |date=September 2012 |title=Unexpectedly many extinct hominins |journal=[[Evolution (journal)|Evolution]] |volume=66 |issue=9 |pages=2969–2974 |doi=10.1111/j.1558-5646.2012.01660.x |issn=0014-3820 |pmid=22946817 |s2cid=13145359 |doi-access=free}}</ref> Evidence has also been found that as much as 6% of the DNA of some modern [[Melanesians]] derive from Denisovans, indicating limited interbreeding in Southeast Asia.<ref name="Reich_2011" /><ref>{{cite journal |last1=Martinón-Torres |first1=María |last2=Dennell |first2=Robin |last3=Bermúdez de Castro |first3=José María |date=February 2011 |title=The Denisova hominin need not be an out of Africa story |journal=Journal of Human Evolution |volume=60 |issue=2 |pages=251–255 |doi=10.1016/j.jhevol.2010.10.005 |issn=0047-2484 |pmid=21129766 |bibcode=2011JHumE..60..251M}}</ref>

Alleles thought to have originated in Neanderthals and Denisovans have been identified at several genetic loci in the genomes of modern humans outside Africa. [[Human leukocyte antigen]] (HLA) haplotypes from Denisovans and Neanderthal represent more than half the HLA alleles of modern Eurasians,<ref name="10.1126/science.1209202" /> indicating strong positive selection for these [[introgressed]] alleles. Corinne Simoneti at Vanderbilt University, in Nashville and her team have found from medical records of 28,000 people of European descent that the presence of Neanderthal DNA segments may be associated with a higher rate of depression.<ref>{{Cite journal |doi=10.1126/science.aad2149 |pmid=26912863 |pmc=4849557 |title=The phenotypic legacy of admixture between modern humans and Neandertals |journal=[[Science (journal)|Science]] |volume=351 |issue=6274 |pages=737–741 |date=2016 |last1=Simonti |first1=C. N. |last2=Vernot |first2=B. |last3=Bastarache |first3=L. |last4=Bottinger |first4=E. |last5=Carrell |first5=D. S. |last6=Chisholm |first6=R. L. |last7=Crosslin |first7=D. R. |last8=Hebbring |first8=S. J. |last9=Jarvik |first9=G. P.| last10=Kullo| first10=I. J. |last11=Li |first11=R. |last12=Pathak |first12=J. |last13=Ritchie |first13=M. D. |last14=Roden |first14=D. M. |last15=Verma |first15=S. S. |last16=Tromp |first16=G. |last17=Prato |first17=J. D. |last18=Bush |first18=W. S. |last19=Akey |first19=J. M. |last20=Denny |first20=J. C. |last21=Capra |first21=J. A. |bibcode=2016Sci...351..737S}}</ref>

The flow of genes from Neanderthal populations to modern humans was not all one way. Sergi Castellano of the Max Planck Institute for [[Evolutionary Anthropology]] reported in 2016 that while Denisovan and Neanderthal genomes are more related to each other than they are to us, Siberian Neanderthal genomes show more similarity to modern human genes than do European Neanderthal populations. This suggests Neanderthal populations interbred with modern humans around 100,000 years ago, probably somewhere in the Near East.<ref>{{cite journal |volume=530 |issue=7591 |title=Ancient gene flow from early modern humans into Eastern Neanderthals |journal=[[Nature (journal)|Nature]] |pages=429–433 |pmid=26886800 |pmc=4933530 |last1=Kuhlwilm |first1=M. |last2=Gronau |first2=I. |last3=Hubisz |first3=M. J. |last4=de Filippo |first4=C. |last5=Prado-Martinez |first5=J. |last6=Kircher |first6=M. |last7=Fu |first7=Q. |last8=Burbano |first8=H. A. |last9=Lalueza-Fox |first9=C. |last10=de la Rasilla |first10=M. |last11=Rosas |first11=A. |last12=Rudan |first12=P. |last13=Brajkovic |first13=D. |last14=Kucan |first14=Ž. |last15=Gušic |first15=I. |last16=Marques-Bonet |first16=T. |last17=Andrés |first17=A. M. |last18=Viola |first18=B. |last19=Pääbo |first19=S. |author19-link=Svante Pääbo |last20=Meyer |first20=M. |last21=Siepel |first21=A. |last22=Castellano |first22=S. |doi=10.1038/nature16544 |bibcode=2016Natur.530..429K |date=2016}}</ref>

Studies of a Neanderthal child at Gibraltar show from brain development and tooth eruption that Neanderthal children may have matured more rapidly than ''Homo sapiens''.<ref>Dean, MC, Stringer, CB et al, (1986) "Age at death of the Neanderthal child from Devil's Tower, Gibraltar and the implications for studies of general growth and development in Neanderthals" (American Journal of Physical Anthropology, Vol 70 Issue 3, July 1986)</ref>