The whole world could soon be seeing red. Instead of being the punchline, redheads will have the last laugh, as a new study reports that humans have been constantly evolving to have flame-colored hair. The finding has challenged previously held ideas about how much natural selection has influenced our DNA over hundreds of thousands of years. Scientists once thought directional selection — a type of natural selection that favors one extreme phenotype over others — was rare in humans. A study

Tag-uri: DNA