David Reich (geneticist)
|Thesis||Genetic analysis of human evolutionary history with implications for gene mapping|
|Doctoral advisor||David B. Goldstein|
David Emil Reich (born 14 July 1974) is a geneticist known for his research into the population genetics of ancient humans, including their migrations and the mixing of populations, discovered by analysis of genome-wide patterns of mutations. He is professor in the department of genetics at the Harvard Medical School, and an associate of the Broad Institute. Reich was highlighted as one of Nature's 10 for his contributions to science in 2015. He received the Dan David Prize in May 2017.
- 1 Early life
- 2 Academic career
- 3 Genetic research
- 4 Books
- 5 See also
- 6 Notes
- 7 References
- 8 Sources
- 9 External links
Reich grew up as part of a Jewish family in Washington, D.C. His parents are novelist Tova Reich (sister of Rabbi Avi Weiss) and Walter Reich, a professor at George Washington University, who served as the first director of the United States Holocaust Memorial Museum. David Reich started out as a sociology major as an undergraduate at Harvard College, but later turned his attention to physics and medicine. After graduation, he attended the University of Oxford, originally with the intent of preparing for medical school.
Reich received a BA in physics from Harvard University and a PhD in zoology from the University of Oxford, St. Catherine's College. He joined Harvard Medical School in 2003. Reich is currently a geneticist and professor in the department of genetics at Harvard Medical School, and an associate of the Broad Institute, whose research studies compare the human genome with those of chimpanzees, Neanderthals and Denisovans.
Reich's genetics research focuses primarily on finding complex genetic patterns that cause susceptibility to common diseases among large populations, rather than finding specific genetic flaws associated with relatively rare illnesses.
Split of chimpanzees and humans (2006)
Reich's research team at Harvard University has produced evidence that, over a span of at least four million years, various parts of the human genome diverged gradually from those of chimpanzees. The split between the human and chimpanzee lineages may have occurred millions of years later than fossilized bones suggest, and the break may not have been as clean as previously thought. The genetic evidence developed by Reich's team suggests that after the two species initially separated, they may have continued interbreeding for several million years. A final genetic split transpired between 6.3 million and 5.4 million years ago.
Indian population (2009)
Reich's 2009 paper Reconstructing Indian population history was a landmark study in the research on India's genepool and the origins of its population. Reich et al. (2009), in a collaborative effort between the Harvard Medical School and the Centre for Cellular and Molecular Biology (CCMB), examined the entire genomes worth 560,000 single-nucleotide polymorphisms (SNPs), as compared to 420 SNPs in prior work. They also cross-compared them with the genomes of other regions available in the global genome database. Through this study, they were able to discern two genetic groups in the majority of populations in India, which they called "Ancestral North Indians" (ANI) and "Ancestral South Indians" (ASI).[note 1] They found that the ANI genes are close to those of Middle Easterners, Central Asians and Europeans whereas the ASI genes are dissimilar to all other known populations outside India.[note 2][note 3] These two distinct groups, which had split ca. 50,000 years ago, formed the basis for the present population of India.
A follow-up study by Moorjani et al. (2013) revealed that the two groups mixed between 1,900 and 4,200 years ago (2200 BCE-100 CE), where-after a shift to endogamy took place and admixture became rare.[note 4] Speaking to Fountain Ink, David Reich stated, "Prior to 4,200 years ago, there were unmixed groups in India. Sometime between 1,900 to 4,200 years ago, profound, pervasive convulsive mixture occurred, affecting every Indo-European and Dravidian group in India without exception." Reich pointed out that their work does not show that a substantial migration occurred during this time.
Metspalu et al. (2011), representing a collaboration between the Estonian Biocenter and CCMB, confirmed that the Indian populations are characterized by two major ancestry components. One of them is spread at comparable frequency and haplotype diversity in populations of South and West Asia and the Caucasus. The second component is more restricted to South Asia and accounts for more than 50% of the ancestry in Indian populations. Haplotype diversity associated with these South Asian ancestry components is significantly higher than that of the components dominating the West Eurasian ancestry palette.
Human genetic map (2011)
Reich was a co-leader, along with statistician Simon Myers, of a team of genetics researchers from Harvard University and the University of Oxford that made the most complete human genetic map then known in July 2011.
Interbreeding of Neanderthals and humans (2010–2012)
Reich's research team significantly contributed to the discovery that Neanderthals and Denisovans interbred with modern human populations as they dispersed from Africa into Eurasia 70,000-30,000 years ago.
Genetic markers for prostate cancer
Reich's lab has received media attention following its discovery of a genetic marker which is linked to an increased likelihood of developing prostate cancer.
Reich has recently suggested that the Indo-European languages may have originated south of the Caucauses, in present day Iran or Armenia: "Ancient DNA available from this time in Anatolia shows no evidence of steppe ancestry similar to that in the Yamnaya (although the evidence here is circumstantial as no ancient DNA from the Hittites themselves has yet been published). This suggests to me that the most likely location of the population that first spoke an Indo-European language was south of the Caucasus Mountains, perhaps in present-day Iran or Armenia, because ancient DNA from people who lived there matches what we would expect for a source population both for the Yamnaya and for ancient Anatolians. If this scenario is right the population sent one branch up into the steppe-mixing with steppe hunter-gatherers in a one-to-one ratio to become the Yamnaya as described earlier- and another to Anatolia to found the ancestors of people there who spoke languages such as Hittite." 
- Reich (2009) excluded the Austro-Asiatic and Tibeto-Burman speakers from their analysis in order to avoid interference.
- Reich (2009): "We analyze 25 diverse groups to provide strong evidence for two ancient populations, genetically divergent, that are ancestral to most Indians today. One, the "Ancestral North Indians" (ANI), is genetically close to Middle Easterners, Central Asians, and Europeans, while the other, the "Ancestral South Indians" (ASI), is as distinct from ANI and East Asians as they are from each other."
- Moorjani et al. (2013): "Most Indian groups descend from a mixture of two genetically divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners, Caucasians, and Europeans; and Ancestral South Indians (ASI) not closely related to groups outside the subcontinent."
- Moorjani et al. (2013): "We report genome-wide data from 73 groups from the Indian subcontinent and analyze linkage disequilibrium to estimate ANI-ASI mixture dates ranging from about 1,900 to 4,200 years ago. In a subset of groups, 100% of the mixture is consistent with having occurred during this period. These results show that India experienced a demographic transformation several thousand years ago, from a region in which major population mixture was common to one in which mixture even between closely related groups became rare because of a shift to endogamy."
- "David Reich | Genetics". genetics.hms.harvard.edu. Retrieved 2018-01-08.
- "Nature's 10". Retrieved 11 April 2018.
- Zimmer, Carl (2018-03-20). "David Reich Unearths Human History Etched in Bone". The New York Times. Retrieved 2018-03-20.
- Rincon, Paul (11 April 2018). "How ancient DNA is transforming our view of the past". BBC. Retrieved 11 April 2018.
- Emile., Reich, David (1999). "Genetic analysis of human evolutionary history with implications for gene mapping".
- ScienceNews.org - 'Hybrid-Driven Evolution: Genomes show complexity of human-chimp split: Not only did the evolutionary parting of human from chimpanzee ancestors occur more recently than had been indicated by previous data, but it also played out over an extended period during which forerunners of people and chimps interbred', Bruce Bower, Science News (May 20, 2006)
- Patterson, N.; Richter, D. J.; Gnerre, S.; Lander, E. S.; Reich, D. (2006). "Genetic evidence for complex speciation of humans and chimpanzees". Nature. 441 (7097): 1103–1108. Bibcode:2006Natur.441.1103P. doi:10.1038/nature04789. PMID 16710306.
- Reich 2009.
- Chakravarti, Aravinda (24 September 2009). "Tracing India's invisible lthreads" (PDF). Nature (News & Views).
- Elie Dolgin (2009), Indian ancestry revealed. The mixing of two distinct lineages led to most modern-day Indians, Nature News
- Srinath Perur, The origins of Indians. What our genes are telling us., Fountain Ink Archived 2016-03-04 at the Wayback Machine.
- Metspalu et al. 2011.
- David Cameron (July 20, 2011). "Detail distinguishes map of African-American genomics". Harvard Gazette. Retrieved July 22, 2011.
- Reich, D.; Green, R.E.; Kircher, M.; Krause, J.; Patterson, N.; Durand, E.Y.; et al. (2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia". Nature. 468 (7327): 1053–1060. Bibcode:2010Natur.468.1053R. doi:10.1038/nature09710. PMC 4306417. PMID 21179161. Reich, D.; Patterson, N.; Kircher, M.; Delfin, F.; Nandineni, M.R.; Pugach, I.; et al. (2011). "Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania". The American Journal of Human Genetics. 89 (4): 516–528. doi:10.1016/j.ajhg.2011.09.005. PMC 3188841. PMID 21944045. Sankararaman, S.; Patterson, N.; Li, H.; Pääbo, S.; Reich, D; Akey, J.M. (2012). "The Date of Interbreeding between Neandertals and Modern Humans". PLoS Genetics. 8 (10): e1002947. doi:10.1371/journal.pgen.1002947. PMC 3464203. PMID 23055938. Carl Zimmer, "Interbreeding with Neanderthals", Discover, March 2013, pp. 38-44.
- Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. By David Reich. New York: Pantheon, 2018.
- Metspalu, Mait; Romero, Irene Gallego; Yunusbayev, Bayazit; Chaubey, Gyaneshwer; Mallick, Chandana Basu; Hudjashov, Georgi; Nelis, Mari; Mägi, Reedik; Metspalu, Ene; Remm, Maido; Pitchappan, Ramasamy; Singh, Lalji; Thangaraj, Kumarasamy; Villems, Richard; Kivisild, Toomas (2011), "Shared and Unique Components of Human Population Structure and Genome-Wide Signals of Positive Selection in South Asia", The American Journal of Human Genetics, 89 (6): 731–744, doi:10.1016/j.ajhg.2011.11.010, ISSN 0002-9297, PMC 3234374, PMID 22152676
- Moorjani, P.; Thangaraj, K.; Patterson, N.; Lipson, M.; Loh, P. R.; Govindaraj, P.; Singh, L. (2013), "Genetic evidence for recent population mixture in India", The American Journal of Human Genetics, 93 (3): 422–438, doi:10.1016/j.ajhg.2013.07.006, PMC 3769933, PMID 23932107
- Reich, David; Thangaraj, Kumarasamy; Patterson, Nick; Price, Alkes L.; Singh, Lalji (2009), "Reconstructing Indian population history", Nature, 461 (7263): 489–494, Bibcode:2009Natur.461..489R, doi:10.1038/nature08365, ISSN 0028-0836, PMC 2842210, PMID 19779445
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