Human Population Genetics

My laboratory is involved in two major areas of research: gene mapping and evolutionary genetics. Our gene mapping efforts are focused on finding genes that cause limb malformation syndromes. Currently, we are working on several of these diseases, including distal arthrogryposis, Freeman-Sheldon syndrome, Gordon syndrome, fibular hypoplasia, and ulnar-mammary syndrome. We have mapped genes for type 1 distal arthrogryposis, ulnar-mammary syndrome, and a variant of Freeman-Sheldon syndrome. Recently we identified mutations in a gene that causes ulnar-mammary syndrome. As our research pinpoints the responsible genes, our understanding of the etiology of these poorly understood diseases will increase, and more accurate diagnosis and prognosis will be possible. In addition, we will learn more about the biology of limb development.

Our evolutionary genetic research involves the analysis of worldwide genetic variation in human mitochondrial and nuclear DNA (including the Y chromosome). We are usingthese data to test a variety of evolutionary hypotheses, including the controversial proposition that modern Homo sapiens originated in Africa and then replaced human populations in other parts of the world. Although mitochondrial and nuclear polymorphisms yield somewhat discordant pictures of human evolution, our recent results show that both types of polymorphisms are consistent with an African origin of modern humans.

We are also engaged in genetic research projects in Finland. We have collected DNA samples and archival data to study genetic distances, genetic diseases, inbreeding, and patterns of drift and gene flow. These results have been used to interpret the high frequencies of genetics diseases that are common in some Finnish populations but rare elsewhere (e.g., von Willebrand disease)