What explains accelerated genetic evolution in human lineage?
By examining patterns of DNA variation in the genome for different human populations, we can determine how much of our evolutionary history was influenced by simple demographic change or, alternatively, by spurts of natural selection. In a recent paper in the Proceedings of the National Academy of Sciences, a large-scale analysis of chromosomal, that is to say DNA polymorphism, data from various geographically and ethnically diverse populations was conducted to test these two competing hypotheses. Although several studies have previously concluded that many gene regions have undergone recent adaptive evolution, The authors of this paper present a simple model of population expansion and migration over the more than 50,000 years that may better explain much of the current global pattern of DNA variation. These interpretations imply that cultural adaptation accompanied by population growth over the past 10,000 to 20,000 years, such as the spread of agriculture and migration into different climatic environments, may have supplied much of the selective pressure that explains recent genetic adaptation in humans.