A comprehensive analysis of the genes of aquatic birds has revealed a family tree dramatically different from traditional relationship groupings based on the birds' body structure, according to a research report to be published in the 7 July 2001 issue of the Journal of the Royal Society and featured on the cover of that issue.
The most startling and unexpected finding of the study is that the closest living relative of the elegant flamingo, with its long legs built for wading, is not another long-legged species of wading bird but the squat grebe, with its short legs built for diving. The two species, whose genes surprisingly are more similar to each other's than to those of any other bird, otherwise show no outward resemblance, according to Blair Hedges, an evolutionary biologist at Penn State.
Hedges leads one of the two research groups that collaborated on the study by separately performing two different kinds of genetic analyses using DNA samples obtained from separate sources. The other group is led by John A. W. Kirsch, professor of zoology and director of the Zoological Museum at the University of Wisconsin. "We knew people might have a hard time accepting these results so we decided to publish our two studies together in the same paper because the weight of the combined evidence is quite strong," Hedges says.
Another surprising implication of the study is that physical features like long legs and webbed feet--traditionally used to group birds of a feather into different flocks on the bird family tree--did not appear just once during the history of bird evolution, as had been the hallmark assumption of the traditional classification system. Instead, the study suggests such structures evolved repeatedly in the history of different aquatic bird species. Because many of the species in the study are located on the "twigs" at the ends of a branch of the bird family tree--not farther back in time on its "trunk"--the study also
Contact: Barbara K. Kennedy