A gene-first approach
To find the genes involved in altitude adaptation, the researchers decided to look for regions of the genome that showed a "signature of selection" a sign that the region has recently experienced natural or sexual selection. Their basic approach was to look for alleles that were frequent among highland Tibetans and rare in a nearby lowland population from Beijing, the Han Chinese. The team reasoned that, because the two populations are so closely related, differences in allele frequency between the two were likely caused by recent selection perhaps the result of the different altitudes at which the two populations live.
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2 Yi, X., Y. Liang, E. Huerta-Sánchez, X. Jin, Z.X.P. Cuo, J.E. Pool, … and J. Wang. 2010. Sequencing of 50 human exomes reveals adaptation to high altitude. Science 329:75-78.
Photo of genome sequencing machine by Jon Callas (CC BY 2.0); Tibetan plateau map adapted from map at china-mike.com
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