Interview with Sarah Tishkoff: Perspectives for Genetic Research in African Populations

Sarah Tishkoff is the David and Lyn Silfen University Associate Professor in Genetics and Biology at the University of Pennsylvania, holding appointments in the Perelman School of Medicine and the School of Arts and Sciences. Dr. Tishkoff studies genetic variation in ethnically diverse Africans in order to reconstruct modern human origins, African population history, and processes of adaptation. Her research examines how genetic variation influences normal variable traits as well as disease susceptibility and drug response. Dr. Tishkoff has long been an advocate for the need for populations in Africa to be represented in human genetic studies so that they may benefit from knowledge about their population history and development of more effective medical treatments.

Dr. Tishkoff received her bachelor's degree in anthropology and genetics from the University of California at Berkeley, and her masters of philosophy and doctorate in genetics from Yale School of Medicine. She taught in the Department of Biology at the University of Maryland at College Park from 2000-2007 and became a faculty member at the University of Pennsylvania in 2008.

Dr. Tishkoff is a recipient of an NIH Pioneer Award, a Packard Career Award, and a Burroughs/Wellcome Fund Career Award. She is currently a member of the editorial boards of Genome Research Journal and G3: Genes Genomes Genetics and is an associate editor of Molecular Biology and Evolution Journal and The Quarterly Review of Biology. Her research is supported by grants from the National Institutes of Health and the National Science Foundation.

Giovanni Destro-Bisol:

Sarah, a significant part of your research work focuses on the genetics of human populations living south of the Sahara desert. Therefore, you can probably explain, better than anyone else, why sub-Saharan Africa is such an important and attractive area for researchers studying human molecular evolution.

Figure 1.

Sarah Tishkoff is the David and Lyn Silfen Univerity Associate Professor in Genetics and Biology at the University of Pennsylvania. Photo courtesy of Sadie Robinson.

Sarah Tishkoff:

Africa is an important region to study for genetic variation for a number of reasons. First is that Africa is thought to be the homeland of all modern humans. If we want to learn more about human origins (e.g., when and where did modern humans evolve and how did they adapt to shifting environments?) then we need to study diversity in Africa. Secondly, Africa is the recent homeland of millions of people whose ancestors were brought to the Americas and elsewhere as slaves. Knowledge of genetic diversity across ethnically diverse Africans will be important for reconstructing ancestry in individuals of recent African descent. Thirdly, study of genetic, phenotypic, and environmental variation in Africa will be important for identifying the genetic and environmental factors that play a role in both normal phenotypic variation as well as in diseases common in Africa and in people of recent African descent (e.g., infectious diseases such as malaria, TB, and HIV and other diseases such as hypertension and prostate cancer). Additionally, little is currently known about genetic variation at genes that play a role in drug response across ethnically diverse Africans. Such knowledge will be important for the development of more effective treatments in these populations. Lastly, because of high levels of genetic, cultural, and climatic diversity in Africa there has likely been local adaptation within populations from different regions practicing diverse lifestyles. Therefore, the possibility of geographically restricted rare, as well as common, functional variants requires the inclusion of a broad range of geographically and ethnically diverse African populations in human genetic studies.

GD-B:

There have been a number of studies of DNA polymorphisms published in the literature which offer contrasting hypotheses regarding the geographic origin of anatomically modern humans. For example, your Science 2009 paper provides compelling evidence that modern human migration originated in southwestern Africa (Tishkoff et al. 2010). However, a recent...