Summary

Many people think evolution requires thousands or even millions of years, but biologists know it can happen fast. Now, thanks to the genomic revolution, researchers can actually track the population-level genetic shifts that mark evolution in action—and they're doing this in humans. Two studies presented at the Biology of Genomes meeting in Cold Spring Harbor, New York, last week show how human genomes have changed over centuries or decades, charting how since Roman times the British have evolved to be taller and fairer, and how just in the last generation a gene that favors cigarette smoking led to early death in some groups. The studies show how the human genome quickly responds to new conditions in subtle but meaningful ways. One study showed continued selection for taller stature, blond hair, and blue eyes in the past 2000 years. The other examined how allele frequencies can change within a lifetime.