Are Humans Still Evolving Body Paragraph 2

The evidence supporting the hypothesis that EPAS1 is responsible for the Tibetans adaptations to altitude is abundant. In one study researchers compared the genome of indigenous highlanders to closely related Han Chinese individuals. The EPAS1 gene displayed the most variation between the two populations. The variation in gene frequencies can likely be explained by natural selection, as a version of the EPAS1 gene was more advantageous to tibetan highlanders and resulted in increased fitness. Another group of researchers sequenced 50 exomes of Tibetans to identify genes showing population specific allele frequency changes. The EPAS1 gene again displayed the strongest signs of natural selection. “One single-nucleotide polymorphism at EPAS1 shows a 78% frequency difference… representing the fastest allele frequency change observed at any human gene to date (Xin Yi et al., 2010).” The adaptations that allow Tibetans to live at high altitudes are conclusive evidence that modern humans are evolving. The traits may have arose through mutation, but since they offered a selective advantage they increased in frequency - a process known as evolution by natural selection.