Evolving Multiple Times
Posted by Shari Horowitz in Tropical Fish Hobbyist Blog on January 24, 2012 at 8:59 am
NEW YORK, New York — Blind Mexican cavefish (Astyanax mexicanus) have not only lost their sight, but have adapted to perpetual darkness by also losing their pigment (albinism) and having altered sleep patterns. Research led by New York University biologists shows that the cavefish are an example of convergent evolution, with several populations repeatedly, and independently, losing their sight and pigmentation. Their study appears in BioMed Central’s open access journal, BMCEvolutionary Biology.
The blind cavefish and the surface dwelling Mexican tetra, despite appearances, are the same species and can interbreed. The cavefish are simply a variant of the Mexican tetra, albeit ones adapted to living in complete darkness. A team of researchers from Portugal, the United States, and Mexico studied the DNA from 11 populations of cavefish (from three geographic regions) and 10 populations of their surface-dwelling cousins to help understand the evolutionary origin of the physical differences between them.
Source: http://www.underwatertimes.com/news.php?article_id=17310420569
Photograph by Richard Borowsky.
Maybe the mutation for no eyes causes enhancement of another sense in the fish, which would make it advantageous in the dark