Neanderthal genetics
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Genetic studies on Neanderthal ancient DNA became possible in the late 1990s.[1] The Neanderthal genome project, established in 2006, presented the first fully sequenced Neanderthal genome in 2013.
Since 2005, evidence for substantial
The divergence time between the Neanderthal and modern human lineages is estimated at between 750,000 and 400,000 years ago. The recent time is suggested by Endicott et al. (2010)[5] and Rieux et al. (2014).[6] A significantly deeper time of parallelism, combined with repeated early admixture events, was calculated by Rogers et al. (2017).[7]
Genome sequencing
In July 2006, the Max Planck Institute for Evolutionary Anthropology and 454 Life Sciences announced that they would sequence the Neanderthal genome over the next two years. It was hoped the comparison would expand understanding of Neanderthals, as well as the evolution of humans and human brains.[8]
In 2008 Richard E. Green et al. from
The project first sequenced the entire genome of a Neanderthal in 2013 by extracting it from the phalanx bone of a 50,000-year-old Siberian Neanderthal.[12]
Among the genes shown to differ between present-day humans and Neanderthals were
A visualisation map of the reference modern-human containing the genome regions with high degree of similarity or with novelty according to a Neanderthal of 50 ka[12] has been built by Pratas et al.[14]
Interbreeding with anatomically modern humans
Researchers addressed the question of possible interbreeding between Neanderthals and
Positive evidence for admixture was first published in May 2010.[13] Neanderthal-inherited genetic material is found in all non- Sub Saharan African populations and was initially reported to comprise 1 to 4 percent of the genome.[13] This fraction was refined to 1.5 to 2.1 percent.[12] Further analyses have found that Neanderthal gene flow is even detectable in African populations, suggesting that some variants obtained from Neanderthals posed a survival advantage.[17]
Approximately 20 percent of Neanderthal DNA survives in modern humans; however, a single human has an average of around 2% Neanderthal DNA overall with some countries and backgrounds having a maximum of 3% per human.[18] Modern human genes involved in making
Research since 2010 refined the picture of interbreeding between Neanderthals,
Kim and Lohmueller (2015) reached similar conclusions:
" According to some researchers, the greater proportion of Neanderthal ancestry in East Asians than in Europeans or West Asians is due to purifying selection is less effective at removing the so-called 'weakly-deleterious' Neanderthal alleles from East Asian populations. Computer simulations of a broad range of models of selection and demography indicate this hypothesis cannot account for the higher proportion of Neanderthal ancestry in East Asians than in Europeans. Instead, complex demographic scenarios, likely involving multiple pulses of Neanderthal admixture, are required to explain the data."[25]
Khrameeva et al. (2014), a German-Russian-Chinese collaboration, compiled an elementary Neanderthal genome based on the Altai individual and three Vindjia individuals. This was compared to a consensus chimpanzee genome as the out-group and to the genome of eleven modern populations (three African, three East Asian, three European). Beyond confirming a greater similarity to the Neanderthal genome in several non-Africans than in Africans, the study also found a difference in the distribution of Neanderthal-derived sites between Europeans and East Asians, suggesting recent evolutionary pressures. Asian populations showed clustering in functional groups related to immune and haematopoietic pathways, while Europeans showed clustering in functional groups related to the lipid catabolic process.[26]
Kuhlwilm et al. (2016) presented evidence for AMH admixture to Neanderthals at roughly 100,000 years ago.[27]
At minimum, research indicates three episodes of interbreeding. The first occurred with some modern humans. The second occurred after the ancestral
2016 research indicates some Neanderthal males might not have viable male offspring with some AMH females. This could explain the reason why no modern man has a Neanderthal Y chromosome.[31]
In October 2023, scientists reported that an anatomically-modern-human-to-Neanderthal admixture event occurred roughly 250,000 years ago, and also noted that roughly 6% of the Altai Neanderthal genome was inherited from anatomically modern humans. [32]
In December 2023, scientists reported that
Epigenetics
Complete DNA methylation maps for Neanderthal and Denisovan individuals were reconstructed in 2014.[36] Differential activity of
See also
- Human evolutionary genetics
- Recent human evolution
- Accretion model of Neanderthal origins
References
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- ^ Brahic, Catherine (3 February 2014). "Humanity's forgotten return to Africa revealed in DNA". New Scientist.
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A. Rieux (2014). "Improved calibration of the human mitochondrial clock using ancient genomes". Molecular Biology and Evolution. 31 (10): 2780–92. PMID 25100861.
- PMID 28784789.; see also: Jordana Cepelewicz, Genetics Spills Secrets From Neanderthals' Lost History, Quanta Magazine, 18 September 2017. "The dating of that schism between the Neanderthals and the Denisovans is surprising because previous research pegged it as much more recent: a 2016 study, for instance, set it at only 450,000 years ago. An earlier separation means we should expect to find many more fossils of both eventually. It also changes the interpretation of some fossils. Take the large-brained hominid bones belonging to a species called Homo heidelbergensis, which lived in Europe and Asia around 600,000 years ago. Paleoanthropologists disagreed about how they relate to other human groups, some positing they were ancestors of both modern humans and Neanderthals, others claim they were a non-ancestral species replaced by the Neanderthals in their spread across Europe."
- ^ Moulson, Geir; Associated Press (July 20, 2006). "Neanderthal genome project launches". NBC News. Retrieved August 22, 2006.
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- ^ "Neanderthal Genome Sequencing Yields Surprising Results And Opens A New Door To Future Studies" (Press release). Lawrence Berkeley National Laboratory. November 16, 2006. Retrieved May 31, 2009.
- ^ Evans PD, Mekel-Bobrov N, Vallender EJ, Hudson RR, Lahn BT (November 2006). "Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage". Proceedings of the National Academy of Sciences of the United States of America. 103 (48): 18178–83.
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- ^ a b "Surprise! 20 Percent of Neanderthal Genome Lives On in Modern Humans, Scientists Find". National Geographic. 29 January 2014. Archived from the original on March 9, 2021. Retrieved October 7, 2016.
- ^ Zimmer, Carl (4 July 2020). "DNA Linked to Covid-19 Was Inherited From Neanderthals, Study Finds - The stretch of six genes seems to increase the risk of severe illness from the coronavirus". The New York Times. Retrieved 5 July 2020.
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"Specifically, genes in the LCP [lipid catabolic process] term had the greatest excess of NLS in populations of European descent, with an average NLS frequency of 20.8±2.6% versus 5.9±0.08% genome wide (two-sided t-test, P<0.0001, n=379 Europeans and n=246 Africans). Further, among examined out-of-Africa human populations, the excess of NLS [Neanderthal-like genomic sites] in LCP genes was only observed in individuals of European descent: the average NLS frequency in Asians is 6.7±0.7% in LCP genes versus 6.2±0.06% genome wide."
Khrameeva, Ekaterina E.; Bozek, Katarzyna; He, Liu; Yan, Zheng; Jiang, Xi; Wei, Yuning; Tang, Kun; Gelfand, Mikhail S.; Prufer, Kay; Kelso, Janet; Paabo, Svante; Giavalisco, Patrick; Lachmann, Michael; Khaitovich, Philipp (2014). "Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans". Nature Communications. 5: 3584. PMID 24690587..
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- ^ Zimmer, Carl (14 December 2023). "Morning Person? You Might Have Neanderthal Genes to Thank. - Hundreds of genetic variants carried by Neanderthals and Denisovans are shared by people who like to get up early". The New York Times. Archived from the original on 14 December 2023. Retrieved 14 December 2023.
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