Originally Posted by bubba13
Interesting. It still surprises me how the Lp complex could become prevalent in the wild. The only thing I can figure is that it may have broken up the contour of individual horses, like zebra striping. But you'd think that the negatives--like eye problems and increased cancer--would outweigh the benefits in this scenario.
There is a theory that spots, just as with the spots on feline leopards and many other animals, are vestiges of what once were stripes. I'm not sure I buy into it, but it is a convincing argument.
As far as the eye and cancer issues, any increase in cancer beyond normal in a horse would likely not be an issue as due to the age of onset it would not interfere with reproduction, thus would not normally be considered a natural selection factor. But the eye issue is a different matter, and you are correct - an inability to escape nocturnal predators should be a natural selection issue that would be normally bred out. Of course it is primarily an issue in homozygous horses, and it may be that the incidence of homozygosity in a mixed population would be low enough to render the issue mostly moot - unless there were a herd exclusively made up of naturally occuring LP horses, which would not be something anyone would expect...