Abstract: A common null hypothesis in evolutionary genetics is that selection coefficients of mutations at a particular site remain constant over evolutionary time. This model has provided a framework for using comparative genomics methods for identifying sites under constraint and that are likely to be functional. In this talk, I will describe three recent studies from my lab challenging this view, showing how selection coefficients have changed throughout evolution. First, I will describe how the distribution of fitness effects of new mutations differs across species. Second, I will describe how the proportion of beneficial mutations is higher in humans than in mice and flies. Lastly, I will discuss how selection coefficients for mutations at noncoding sites have changed throughout mammalian evolution. Our work suggests selection coefficients are dynamic, influenced by population size, organismal complexity, epistasis, and the environment.
About Dr. Lohmueller:
Kirk Lohmueller is an Associate Professor in the Department of Ecology and Evolutionary Biology as well as Human Genetics at UCLA. He is a population geneticist who studies a wide range of organisms, including humans, mice, dogs, wolves, foxes, birds, sea otters, and plants. A major topic in Lohmueller’s research has focused on understanding how deleterious mutations impact genomes and complex traits.
Lohmueller received his undergraduate degree from Georgetown University in 2005 and his PhD from Cornell University, advised by Andrew Clark and Carlos Bustamante. Lohmueller then was a Miller Fellow at UC Berkeley, hosted by Rasmus Nielsen. Lohmueller joined the faculty at UCLA in 2013 and has received several awards including a Sloan Research Fellowship, a Searle Scholar Award, and a Hellman Faculty Fellowship. His research has been supported by the NIH, NSF, and NIJ.
Link to the Lohmueller Lab: