As a child, geneticist Bo Xia wondered why humans don't have tails. Years later, while recovering from a tailbone injury ...

“Future experiments will test the theory that in an ancient evolutionary trade-off, the loss of a tail in humans contributed to the neural tube birth defects,” said study author Dr. Itai Yanai.

Humans do not have tails, but do we have “what it takes” for a tail? Hens don’t have teeth, but they have the genes for it. With atavism, it is as if our genomes serve as archives of our ...