Time to give thanks for your genome. A new study finds that at some point in our evolutionary history, humans lost a stretch of DNA that would have otherwise promoted the growth of spines on the penis.
The genetic loss is just one of millions that separates us from our closest primate relative, the chimpanzee, researchers report in the March 10 issue of the journal Nature. The team also reported the disappearance of a growth-suppressing genetic switch. That loss may have contributed to the enlargement of the human brain.