with Rasmus Nielsen (University of California, Berkeley and University of Copenhagen) | March 17, 2015 - 12h00 | CIBIO-InBIO, Vairão




As organisms adapt to new environments, Darwinian selection will act on genes of importance for the organisms survival in the new environment. At the DNA level, we can find traces of this selection by comparing DNA sequences within and between species. This allows us to identify genes that change functionally in response to the changes in the environment. In this talk I will give a couple of examples of this. In the first example we compare polar bears and brown bears, to identify genes under selection in the polar bear lineage. We show that genes under positive selection in the polar bear lineage are functionally enriched for functions related to the cardiovascular system. We hypothesize that this enrichment is caused by a change in diet in polar bears, from omnivorous to a high-lipid diet consisting mostly of seals. In the second example we investigate genes under high-latitude adaptation in Tibetans. We show that Tibetans have a variant of a gene controlling blood hemoglobin concentration that was introgressed into Tibetans, or their ancestors, from an ancestral hominid species - the Denisovans.


Rasmus Nielsen is a professor of computational biology at UC Berkeley and a professor of biology at University of Copenhagen. His research focuses on statistical and computational aspects of evolutionary theory and genetics. One of the central problems he has been interested in is the molecular basis of evolutionary adaptation. What happens at the molecular levels as one species is transformed into another over evolutionary time? To address this question he has developed a number of computational methods and applied them to large scale genomic data, such as genomic comparisons of humans and chimpanzees. Rasmus Nielsen has also worked on statistical methods in other aspects of population genetics, medical genetics, phylogenetics, molecular ecology, and molecular evolution. He has been teaching courses in Population Genetics, Human Genetics, Statistical Genomics, Bioinformatics, and Evolution. His students work on both applied and theoretical problems in population genetics, statistical genetics and evolution. Rasmus Nielsen has published 180 ISI listed peer reviewed papers, including 33 papers in Science and Nature.


[Host: Nuno Ferrand de Almeida, Population Genetics, Hybridization and Speciation]