University of Maryland biologists have identified how changes in both behavior and genetics led to the evolution of the Mexican blind cavefish (Astyanax mexicanus) from its sighted, surface-dwelling ancestor. In research published in the August 12, 2010 online edition of the journal Current Biology, Professor William Jeffery, together with postdoctoral associates Masato Yoshizawa, and pela Gorički, and Assistant Professor Daphne Soares in the Department of Biology, provide new information that shows how behavioral and genetic traits coevolved to compensate for the loss of vision in cavefish and to help them find food in darkness. This is the first time that a clear link has been identified between behavior, genetics, and evolution in Mexican blind cavefish, which are considered an excellent model for studying evolution.
Why Study Blind Cave Fish
Worldwide, about 80 different species of cave-dwelling fish have evolved from surface-dwelling fish, but in most cases the surface-dwelling ancestor has disappeared. "The Mexican blind cavefish is one of the only cases where a similar ancestor still exists," explains Professor Jeffery. "Except for the loss of eyes and pigment seen in the cave-dwelling form, the surface and cave-dwellers are hard to tell apart. You can study evolution very nicely if you have both the ancestral and derived forms of evolving animals."
Jeffery is a leading expert on the developmental and evolutionary genetics of the blind cavefish. His previous research provided evidence that the loss of eyes in blind cavefish is the result of natural selection, and has inspired other researchers to take up Astyanax as a model system for studying eye loss and evolution in general. Studying the evolution of cave fish may help provide clues about human forms of blindness such as macular degeneration and cataracts, and the University of Maryland team is also exploring how studies of cave fish metabolism might be used to be
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University of Maryland