Gene found that controls beak size in Darwin’s finches

Drought survivors reveal molecular details of famous evolution story

Geospiza fortis

FAMOUS FINCH  Medium ground finches (Geospiza fortis, shown) underwent a shift from big beaks to small ones following a drought. Most of that shift was traced to big- and small-beak variants of a gene called HMGA2.

P.R. Grant

Natural selection can sometimes work one gene at time, a new study of Darwin’s finches suggests.