November 6 2014

5:00 pm 154 BSRB

EcoEvoPub Series

Graduate Student Presentations



Department of Ecology and Evolutionary Biology
Selection and reduced population size cannot explain higher amounts of Neanderthal ancestry in East Asian than European human populations

The authors are: Bernard Kim and Kirk Lohmueller

It has been hypothesized that the greater proportion of Neanderthal ancestry in East Asians compared to Europeans is due to purifying selection being less effective at removing weakly deleterious Neanderthal alleles from East Asian populations. Using simulations of a broad range of models of selection and demography, we show this hypothesis cannot account for the higher proportion of Neanderthal ancestry in East Asians than in Europeans. Instead, more complex demographic scenarios, likely involving multiple pulses of Neanderthal admixture, are required to explain the data.

Department of Ecology and Evolutionary Biology

“A framework for utilizing genomics in the conservation of wild populations”

In September, the World Wildlife Fund made headlines by declaring that vertebrate populations have dropped by half during the past forty years. While the advent of genomic sequencing has already transformed medicine and studies of model organisms, it is only beginning to make an impact in the conservation of wild species. The maintenance of adaptive variation is imperative for conserving populations, but directly surveying such variation in wild species is intractable for many reasons, and neutral variable markers are routinely assayed as a proxy. Using the case of the island fox (Urocyon littoralis), a species endemic to California’s Channel Islands, I propose a framework for leveraging whole genome sequences to discover loci harboring critical adaptive variation. The island fox has a striking deficit of neutral variation, but functional variation, for instance, in the immune genes of the major histocompatibility complex (MHC) has persisted. Although genomic sequencing was prohibitively expensive and difficult several years ago, it is now relatively cheap and bioinformatic tools for analysis are readily available, making it a feasible endeavor for conservation programs. Both the results and methods from this study will enable the conservation of other rare species, or species reduced to small population sizes, through effective management of genetic biodiversity.











































































































































































































































































































































































































































































































































































































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