Denisovans

From Metapedia
Jump to: navigation, search

The denisovans were a group of archaic humans in the genus Homo. The species is sometimes given the name Homo sp. Altai,[1] and Homo sapiens ssp. Denisova.[2][3] The name derives from the Denisova Cave in the Altai Mountains in Siberia which contained fossils from Denisovans.

Genetic studes suggests that Denisovans shared a common origin with Neanderthals, that they ranged from Siberia to South-East Asia, and that they lived among and interbred with the ancestors of some modern humans, with about 3% to 5% of the DNA of Australoids deriving from Denisovans.[4][5][6]

Genetic analysis have further suggested that this new species was the result of an earlier migration out of Africa, distinct from the later out-of-Africa migrations associated with modern humans, but also distinct from the earlier African exodus of Homo erectus.[7] The existence of this distant branch creates a much more complex picture of humankind during the late Pleistocene.[8] This work shows that the Denisovans were actually a sister group to the Neanderthals,[9] branching off from the human lineage 600,000 years ago, and diverging from Neanderthals, probably in the Middle East, 200,000 years later.[10]

A 2013 study stated that mainland Asians and Native Americans had around 0.2% Denisovan ancestry.[11] However, a 2016 study stated that "Modern humans carry remnants of DNA from interbreeding events with archaic lineages, such as Neandertals. However, people from Oceania also retain genes from a second ancient lineage, the Denisovans. Vernot et al. surveyed archaic genomic sequences in a worldwide sample of modern humans, including 35 individuals from the Melanesian Islands. All non-African genomes surveyed contained Neandertal DNA, but a significant Denisovan component was found only in the Melanesians. Reconstruction of this genetic history suggests that Neandertals bred with modern humans multiple times, but Denosivans only once, in ancestors of modern-day Melanesians."[12]

Little is known of the precise anatomical features of the Denisovans, since the only physical remains discovered thus far are a finger bone, two teeth, and a toe bone. The finger bone is unusually broad and robust, well outside the variation seen in modern people. Surprisingly, it belonged to a female, indicating that the Denisovans were extremely robust, perhaps similar in build to the Neanderthals. The tooth that has been characterized shares no derived morphological features with Neanderthal or modern humans.[13]

References

  1. Exploring Taxonomy. European Molecular Biology Laboratory, Wellcome Trust. Retrieved on 27 October 2015.
  2. Homo sapiens ssp. Denisova. NCBI - Taxonomy Browser. NCBI. Retrieved on 2015-10-28.
  3. Taxonomy - Homo sapiens ssp. Denisova (Denisova hominin). UniProt. Retrieved on 2015-10-28.
  4. Carl Zimmer (22 December 2010). "Denisovans Were Neanderthals' Cousins, DNA Analysis Reveals". NYTimes.com. http://www.nytimes.com/2010/12/23/science/23ancestor.html?hp. Retrieved 22 December 2010. name="Callaway.
  5. "Callaway, Ewen (22 September 2011), "First Aboriginal genome sequenced", Nature (Nature News), doi:10.1038/news.2011.551, http://www.nature.com/news/2011/110922/full/news.2011.551.html 
  6. "About 3% to 5% of the DNA of people from Melanesia (islands in the south-west Pacific Ocean), Australia and New Guinea as well as aboriginal people from the Philippines comes from the Denisovans." Oldest human DNA found in Spain --Elizabeth Landau's interview of Svante Paabo, accessdate=2013-12-10
  7. Katsnelson, Alla (24 March 2010), "New hominin found via mtDNA", The Scientist, http://www.the-scientist.com/blog/display/57254/#ixzz0j820ioz1 
  8. Sample, Ian (24 March 2010), "New species of human ancestor found in Siberia", The Guardian, http://www.guardian.co.uk/science/2010/mar/24/new-human-species-siberia 
  9. Nature Vol 468, p.1053
  10. Marchall, Michael (April), op cit p.36
  11. Prüfer, Kay (2013). "The complete genome sequence of a Neanderthal from the Altai Mountains". Nature 505 (7481): 43–49. doi:10.1038/nature12886. Bibcode2014Natur.505...43P. Retrieved on 1 March 2014.
  12. Zahn, L. M. (2016). Denisovan DNA retained in Melanesians. Science, 352(6282), 183-183. http://science.sciencemag.org/content/352/6282/235?utm_campaign=email-sci-toc&et_rid=120011976&et_cid=400756
  13. Reich, David; Green, Richard E.; Kircher, Martin; Krause, Johannes; Patterson, Nick; Durand, Eric Y.; Viola, Bence; Briggs, Adrian W. et al. (2010), "Genetic history of an archaic hominin group from Denisova Cave in Siberia", Nature 468 (7327): 1053–1060, doi:10.1038/nature09710, PMID 21179161 
Part of this article consists of modified text from Wikipedia, and the article is therefore licensed under GFDL.