The Evolution of Flightless Birds: Study explores the genetics behind how they developed
"Since Darwin’s era, scientists have wondered how flightless birds like emus, ostriches, kiwis, cassowaries, and others are related, and for decades the assumption was that they must all share a common ancestor who abandoned the skies for a more grounded life.
By the early 2000s, new research using genetic tools upended that story, and instead pointed to the idea that flightlessness evolved many times throughout history. Left unanswered, however, were questions about whether evolution had pulled similar or different genetic levers in each of those independent avian lineages.
A team of Harvard researchers believes they may now have part of the answer."