A gene mutation turned these fish into intrepid explorers

The 240 species of cichlid fish in Africa’s Lake Tanganyika come in an astonishing variety of shapes and sizes, from the paper clip–size “sheller” that lives in abandoned snail shells to the nearly meter-long emperor cichlid. Biologists have long wondered what drove this burst of evolutionary creativity. Now, researchers have demonstrated what many suspected but had not been able to prove: that the behavior of an ancestral species—in this case, an appetite for exploration—set the stage for the rapid evolution. The work, which appears today in Science ,  also ties this behavioral trait to a specific genetic mutation . “To find one gene that makes a big difference [in behavior] is very exciting, as you don’t see that very often,” says Martha Muñoz, an evolutionary biologist at Yale University who was not involved with the work. In the 10 million years since the 32,000-square-kilometer Lake Tanganyika formed, filling a giant crack in Africa’s Rift Valley, its cichlid fish have rapidly evolved to take advantage of the lake’s diverse habitats, which include both rocky and sandy bottoms and areas with and without plant cover. Some cichlids specialize in eating plankton; others live on aquatic plants, eggs, invertebrates, and even other fish. The diversity of lifestyles has brought a panoply of body and mouth shapes and sizes. Ever since Darwin examined variation in the beaks of Galápagos finches, many studies have looke...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research