Using the Phase II HapMap data, a team led by researchers at the Broad Institute of MIT and Harvard identified hundreds of genomic regions that carry the hallmarks of recent positive natural selection. These regions are large, often extending for millions of nucleotides and including multiple genes. Thus, the researchers developed a set of computational guidelines to help locate the single letter changes that formed the focal points for evolutionary change.
The work uncovered several intriguing genetic variations that could provide novel insights into the biological forces underlying natural selection in humans. Two differences, which are common primarily in Asian populations, lie within the EDAR and EDA2R genes. In humans, these genes function together to form hair follicles and sweat glands, as well as other structures.
The researchers also identified DNA variations in African populations that may be linked to resistance to Lassa fever, a viral infection common in Western Africa. These changes lie in two genes, LARGE and DMD, which are involved in viral entry into cells. The findings help underscore one of the studys key themes that multiple genes, acting together in the same biological process, often show signs of positive selection, both in humans and other organisms. Integrating these data may bolster efforts to understand the biological consequences of human genetic variation.
Human history and the genome have been dramatically shaped by environmental factors, diet and infectious disease, said co-first author Pardis Sabeti, Ph.D., who is a postdoctoral fellow at the Broad Institute of MIT and Harvard. The gene variants identified in our study open new windows on these evolutionary forces and provide a launching point for future biological studies of human adaptation.
The effort to build the improved HapMap relied heavily on the high-throughput genotyping capacity of Perlegen Sciences, Inc., of Mountain View, C
|Contact: Geoff Spencer|
NIH/National Human Genome Research Institute