VARIATIONS ON A THEME: Natural selection is one factor in people’s genetic differences, but migration, population changes and chance also play a role
Local pressures such as climate or diet that affect natural selection are only partly responsible for differences in the genetic makeup of human populations, a new study finds. Migrations, the expansions and contractions of populations and the vagaries of genetic chance also play a role.
“It’s easy to imagine that natural selection could have led to human populations strongly diverging from each other as they adapted to the different environments they encountered as they spread around the world,” said Graham Coop, an assistant professor of evolution and ecology, and lead author of the paper describing the study. “But what excites me about this work is that we’re showing that a population’s history and migrations between groups have had a strong role in limiting and shaping how populations adapted to their environments.”
The study, led by Jonathan Pritchard, a Howard Hughes Medical Institute investigator at the University of Chicago, was published June 5 in the online journal PLoS Genetics.