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 evolutionary ...

All vertebrate embryos follow a common developmental path due to their common ancestry. All have a set of very similar genes (the homeobox genes) that define their basic body plan. As they grow, the ...