Research
Human evolution and natural selection
A mutation in a gene is under positive or directional selection if it confers a fitness benefit. To identify genes subject to positive selection in genomes of closely related species, such as humans and chimpanzees, can help identify genes responsible for species differences. It also speaks to the question whether observed genetic differences between human races reflect different adaptations. In addition, on the level of individual genes, it allows identification of functionally important regions of a gene and the encoded proteins. It is thus also of potential interest to protein engineers who alter proteins of known function to produce new functions. When a gene is subject to positive selection, only a small region of the gene typically experiences beneficial amino acid changes. Most existing assays to detect positive selection cannot easily identify these small regions. We develop tests that overcome this limitation, and use them to identify genes that have been positively selected since the human-chimpanzee divergence, as well as genes that are responsible for differences among human populations. The identification of gene regions subject to positive selection will help us identify the functionally important parts of positively selected genes.
Selected Publications
Wagner, A. (2007) Rapid detection of positive selection in genes and genomes through variation clusters. Genetics 176: 2451–2463. [PDF] 