Blind Cavefish and Vision in Beetles

There are two interesting vision related studies out. National Geographic has the first, Blind Cavefish Can Produce Sighted Offspring:

“Evolution’s palette is varied,” said study author Richard Borowsky of New York University in a statement.
“Restoration of the ability to see comes in a single generation because the populations residing in different caves are blind for different reasons–i.e., different sets of genes are nonfunctional in the different populations.”

The National Geographic article is based on research appearing in Current Biology (it is not open access, so if someone could send me a copy I would appreciate it)
Science Daily has the second:

The opsin gene family is central to vision. The authors found that the beetle’s compound eye retina lacked the blue-opsin encoding photoreceptors. Their work also identified the red flour beetle as the first example of an insect species that switches on two opsin genes across the entire retina. This co-expression of genes violates the ‘one receptor rule’ of sensory cells.


One Response

  1. Actually, after that first cavefish paper came out, another really interesting one followed it within days. I wrote about that second one for Nature, but for those of you without access, it found that hte larvae of blind cavefish can sense light, even though they have lost their eyes over a million years of evolution. The young fish can detect an overhead shadow and seek shelter by swimming towards it.
    The fish are eyeless as adults but have some basic eye components as larvae. However, when they were cut them out, the fish still responded to shadows. The behaviour is driven by the pineal gland, which still contains the light-sensitive pigment rhodopsin.
    The authors suggested two theories for why the pineal gland could still detect light. The gland also supplies the body with melatonin, a key reproductive and seasonal growth hormone and the twin roles as hormone factory and light detector are tightly linked. The light sensitivity could be a useless function that’s retained because it is linked to an indispensable function. Alternatively, the light-sensing function may help the fish to avoid the odd ray of light that makes its way into caves through windows in the roof and where they would be more vulnerable to sighted predators.
    I also blogged about the first cavefish story you mentioned.

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