Asked by: Keanu Ghorbanian, Bournemouth
As long as we continue to reproduce at different rates, we can’t stop evolving. However, selection pressures on us have changed. Modern medicine means that many people now live, reproduce and pass on genes that would previously have been eliminated. Strength and size are not now as relevant, and men tend to have fewer children earlier in life than they used to. All this affects which genes remain in the human gene pool, changing the direction of human evolution rather than ending it.
Many new traits have appeared and spread, such as the ability to digest milk as an adult, which most Europeans have and most Africans don’t. The genetic change responsible happened between 5,000 and 10,000 years ago, around the time that dairy farming was widely adopted. In a 2007 study of over 3 million DNA variants, about 1,800 human gene variations were found that had evolved in fairly recent times, including mutations aiding malaria resistance and brain development. Some can even be observed today. In parts of South Africa where half the women are infected with HIV, some of them have genes providing an immune system that can throw off the infection. These women are more likely to survive and pass on those genes to their children.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.