Subterranean Fishes of the World

5788

2016

bioRxiv preprint June 9th 2016

Now published in BMC Evolutionary Biology 17:45. See URL

Blindness has evolved repeatedly in cave-dwelling organisms, and investigating the loss of sight in cave dwellers presents an opportunity to understand the operation of fundamental evolutionary processes, including drift, selection, mutation, andmigration. The observation of blind organisms has prompted many hypotheses for their blindness, including both accumulation of neutral, loss-of-functionmutations and adaptation to darkness. Here wemodel the evolution of blindness in caves. Thismodel captures the interaction of three forces: (1) selection favoring alleles causing blindness, (2) immigration of sightedness alleles from a surface population, and (3) loss-of-function mutations creating blindness alleles. We investigated the dynamics of this model and determined selection-strength thresholds that result in blindness evolving in caves despite immigration of sightedness alleles from the surface. Our results indicate that strong selection is required for the evolution of blindness in cave-dwelling organisms, which is consistent with recent work suggesting a highmetabolic cost of eye development.

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