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Background: Blindness has evolved repeatedly in cave-dwelling organisms, and many hypotheses have been proposed to explain this observation, including both accumulation of neutral loss-of-function mutations and adaptation to darkness. Investigating the loss of sight in cave dwellers presents an opportunity to

Background: Blindness has evolved repeatedly in cave-dwelling organisms, and many hypotheses have been proposed to explain this observation, including both accumulation of neutral loss-of-function mutations and adaptation to darkness. Investigating the loss of sight in cave dwellers presents an opportunity to understand the operation of fundamental evolutionary processes, including drift, selection, mutation, and migration.

Results: Here we model the evolution of blindness in caves. This model captures the interaction of three forces: (1) selection favoring alleles causing blindness, (2) immigration of sightedness alleles from a surface population, and (3) 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. We estimate that the selection coefficient for blindness would need to be at least 0.005 (and maybe as high as 0.5) for blindness to evolve in the model cave-organism, Astyanax mexicanus.

Conclusions: 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 high metabolic cost of eye development.

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    Title
    • The Importance of Selection in the Evolution of Blindness in Cavefish
    Contributors
    Date Created
    2017-02-07
    Resource Type
  • Text
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    Identifier
    • Digital object identifier: 10.1186/s12862-017-0876-4
    • Identifier Type
      International standard serial number
      Identifier Value
      1471-2148
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    • The electronic version of this article is the complete one and can be found online at: https://bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-017-0876-4

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    Cartwright, R. A., Schwartz, R. S., Merry, A. L., & Howell, M. M. (2017). The importance of selection in the evolution of blindness in cavefish. BMC Evolutionary Biology, 17(45). doi:10.1186/s12862-017-0876-4

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