APART from a yap out of proportion to their size, what do chihuahuas, terriers and pekinese have in common? The answer is a mutation in a single gene. The variant is found in so many small breeds that it must have been present early in the history of dogs’ domestication.
A team led by Elaine Ostrander of the National Human Genome Research Institute in Bethesda, Maryland, looked at Portuguese water dogs, which come in an unusually wide range of sizes. The smaller dogs tended to carry a particular variant of the gene for the important growth regulator insulin-like growth factor…
