Blind as a fish January 18, 2008Posted by David Corney in Uncategorized.
Having just written a few days ago about nocturnal vision and moths that can see by starlight, I was intrigued to read about some blind cave fish via Living the Scientific Life. The theory is that over millions of years of living in perpetual darkness, these fish mutated until they no longer grew eyes, either to save the effort and energy, or because eyes are delicate and prone to infection. The news is that by taking fish from different populations and breeding hybrids, fully-functioning eyes reappeared in a single generation! It seems that each population mutated in a different way, so at least some hybrid offspring had all the “original” seeing genes still there. Populations matter in genetics.
One thought: if moths can see (in colour, no less) by something as faint as starlight, and these different populations of fish independently gave up having eyes altogether, those caves must be very dark. Very dark indeed…
I liked the final quote from the paper, too:
This observation underscores the power of a well defined environment to repeatedly direct the evolution of the same end phenotype, regardless of initial genotype.
Full paper: Richard Borowsky. Restoring sight in blind cavefish (2008). Current Biology 8 R23-R24 doi:10.1016/j.cub.2007.11.023