Part I: African Genomics: Human Evolution
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Tishkoff begins with an overview of the evolution of modern humans and their migration out of Africa. She explains how and why population geneticists study both nuclear and mitochondrial DNA and how DNA comparisons have allowed scientists to determine when distinct hominid groups diverged and when and where these populations migrated across the globe.
In Part 2, Tishkoff moves to the study of genetic diversity in present day African and African America populations. Genetic variation is higher in Africans than in Europeans or Asians, a result of the evolutionary history of humans. Patterns of diversity at specific genetic loci provide insight into the migrations and mixing of specific linguistic groups within Africa, as well as information about the ancestry of African Americans.
In the final part of her talk, Tishkoff describes two examples of natural selection in humans. She and her colleagues identified 3 novel genetic variants associated with the ability of some African pastoralists to digest lactose. Using high coverage genome sequencing, Tishkoff also identified a candidate chromosomal region associated with short stature in Pygmies. Interestingly, this same region showed enrichment for genes involved in pituitary function such as metabolism and immunity. These results suggest that adaptation to local environments may result in region specific genetic adaptation.
Sarah Tishkoff studied anthropology and genetics as an undergraduate at the University of California, Berkeley. She received her PhD in genetics from Yale University and was a post-doctoral fellow at Pennsylvania State University. From 2000-2007, she was a faculty member in the Department of Biology at the University of Maryland. Currently, Dr. Tishkoff is the David and Lyn Silfen University Professor at the University of Pennsylvania in the Departments of Genetics and Biology.
Tishkoff’s lab studies genetic variation at the genome level in populations throughout the world, with an emphasis on Africa. She is interested in understanding how evolutionary forces have shaped and maintained genetic variation. Were genetic mutations now associated with common diseases such as diabetes or hypertension originally adaptive to historical environments? Could they have provided resistance to local infectious diseases or other benefits? Tishkoff also uses genetic data to study human evolution and human migration; both ancient and more recent migrations such as the slave trade.
Tishkoff’s innovative research has been recognized with numerous awards including the NIH Director’s Pioneer Award for scientists of exceptional creativity.
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Eltis D and Richardson D. 2010. Atlas of the Transatlantic Slave Trade. Yale University Press.
The evolution of human genetic and phenotypic variation in Africa.
Campbell MC, Tishkoff SA.
Curr Biol. 2010 Feb 23;20(4):R166-73.
Recent human adaptation: genomic approaches, interpretation and insights.
Scheinfeldt LB, Tishkoff SA.
Nat Rev Genet. 2013 Oct;14(10):692-702.
The genetic structure and history of Africans and African Americans.
Tishkoff SA, Reed FA, Friedlaender FR, et al., Science. 2009 May 22;324(5930):1035-44.
Lachance J, Vernot B, Elbers CC, Ferwerda B, Froment A, Bodo JM, Lema G, Fu W, Nyambo TB, Rebbeck TR, Zhang K, Akey JM, Tishkoff SA.
Cell. 2012 Aug 3;150(3):457-69.
Jarvis JP, Scheinfeldt LB, Soi S, Lambert C, Omberg L, Ferwerda B, Froment A, Bodo JM, Beggs W, Hoffman G, Mezey J, Tishkoff SA.
PLoS Genet. 2012;8(4):e1002641.
Tishkoff SA, Reed FA, Ranciaro A, Voight BF, Babbitt CC, Silverman JS, Powell K, Mortensen HM, Hirbo JB, Osman M, Ibrahim M, Omar SA, Lema G, Nyambo TB, Ghori J, Bumpstead S, Pritchard JK, Wray GA, Deloukas P.
Nat Genet. 2007 Jan;39(1):31-40.