Roots of milk drinking revealed by South Asian genomes: Natural selection was at work—but only in populations with no alternative to dairy.

The article focuses on a study examining the genetic basis of lactase persistence, the ability to digest milk into adulthood, particularly in South Asia. It highlights that while lactase persistence genes are prevalent in certain populations, their spread in South Asia is largely attributed to ancestry rather than strong selective pressure from milk consumption, contrasting with European populations. However, specific groups like the Toda in South India and the Gujjar in Pakistan show evidence of significant selective pressure due to their pastoralist lifestyles, which heavily rely on dairy. The findings suggest that the advantages of lactase persistence are most pronounced in populations that depend on dairy, providing new insights into the evolution of this trait. [Extracted from the article]