How a ‘rogue’ chunk of DNA scrambled the bird family tree

Doves and flamingos no longer need to invite each other to family reunions now that the bird family tree has sprouted new branches. In recent years, many scientists believed the most modern avian species could be grouped into one of two major categories. But a pair of papers published today suggests this view of avian evolution is wrong—and that the bird family tree likely has twice as many branches. The error arose, the researchers report, because a small segment of genetic material spent millions of years essentially frozen in time. The discovery “provides a cautionary tale” for other scientists, says Scott Edwards, an ornithologist at Harvard University who wasn’t involved in the new research. Even sophisticated methods of tracing family trees, or phylogenetic analysis, can be misled by a single “rogue” piece of DNA, he notes. Some 66 million years ago, a small group of winged dinosaurs survived the asteroid impact that wiped out most of their kin. Today, the descendants of these “early birds” have diversified into more than 10,000 species of flying feathered fauna that span a dazzling array of sizes, shapes, and colors. Exactly how birds came to dominate our skies remains something of a mystery, however. Ever advancing DNA sequencing techniques have unraveled evolutionary relationships in many other species. But those connections between birds have always been notoriously tricky to pin down, says Edward Braun, an evolutionary geneticist a...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research