GEE Seminar - Professor Iain Mathieson, University of Pennsylvania

Academic Host: Karoline Kuchenbaecker
Abstract: Large datasets of ancient and present-day genomes allow us to investigate historical and ongoing episodes of natural selection in humans. Using time series of hundreds of ancient genomes from Britain, we show that the dominant selective pressure in the past 5,000 years was lack of vitamin D and consequent calcium deficiency, with limited evidence of polygenic selection on complex traits. In contrast, when we use genomes of living people to investigate selection over the past 50 years, we identify loci associated with a range of biological and behavioral traits, but very little overlap with historical selection signals. The one locus that does overlap–FADS1–has been under fluctuating selection for tens of hundreds of thousands of years, likely related to changes in diet, though the mechanism is speculative. Finally, by comparing information from ancient DNA, skeletal measurements, stable isotope and paleopathology data, we investigate genetic and environmental factors associated with changes in stature over time. We find examples of change that may be genetic, and others that are definitely environmental. Overall, our results illustrate the dynamic landscape of recent human evolution, and both the opportunities and limits of genomics to learn about that landscape.