St. Louis, March 27, 1998 -- Lizards may not get the limelight in beer commercials, but thanks to biologists at Washington University in St. Louis, the slighted creatures now have Marquee value in evolution and genetics.
A team led by Jonathan B. Losos, Ph.D., associate professor of biology in Arts and Sciences at Washington University, has discovered that remarkably similar lizard communities have evolved independently on different islands in the Caribbean. Losos and his colleagues examined DNA of 56 species found throughout the large Caribbean Islands of Puerto Rico, Cuba, Jamaica and the Greater Antilles. Using several common genes of different species they developed a 'family tree' of these species, the most commonly observed in the Caribbean, to test theories on evolutionary history of the Anoles.
The study reveals a perfect example of an evolutionary concept known as "convergence", where species evolve in similar adaptations to the environment despite living geographically apart. Although evolutionary convergence has been taken as evidence for the working of natural selection, the study is unique in showing that entire communities have converged. This goes against the grain of most evolutionary thought which stresses that random events -- a meteorite striking Earth or a hurricane wiping out island species , for example -- play unpredictable roles that send evolutionary diversification down different pathways.
The results were published in the March 27, 1998 issue of Science magazine.
For the past decade Losos and various collaborators have surveyed the
Caribbean Island Anolis populations and documented how species differ in their
habitat use and body proportions. Detailed studies on more than 50 of the 150
Caribbean anole species indicate that species have adapted to use different
parts of the environment by evolving differences in limb length, toepad size and
Contact: Tony Fitzpatrick
Washington University in St. Louis