Four generations of women and girls from a single family in Gambia.CURRENT BIOLOGY, COURTIOL ET AL In 1974, the UK Medical Research Council (MRC) set up clinics in two rural villages in Gambia’s West Kiang district, offering free medical care to locals. The effect was dramatic. Thanks to good health care, better infrastructure, and accessible contraception, the villagers started living longer and having fewer children.
Over a short time, the district went through a modern-day demographic transition—a well-known fall in birth and death rates typically seen when human societies move to industrialized economies—causing natural selection to act upon the population in noticeably altered ways, according to a study published today (April 25) in Current Biology.
Alexandre Courtiol from the Leibniz Institute for Zoo and Wildlife Research and Ian Rickard from Durham University found that before 1974, shorter, fatter women had the highest relative fitness—measured by the number of descendants they leave behind. But since the clinic was built, selection pressures have flip-flopped so that taller, thinner women now have the advantage.
Their results are the latest to challenge the idea that modern humans have stopped evolving due to industrialization and ...
