ADAPTIVE EVOLUTION OF SLEEP LOSS AND ALBINISM THROUGH MUTATIONS IN OCA2 IN ASTYANAX MEXICANUS

Adaptation to any environment through the course of its evolution involves the alteration of multiple traits to ensure survival, Astyanax mexicanus is a notable example of this. Some of the most notable differences between the surface and cave populations are loss of pigmentation, decreased sleep, and reduced eyes. 208 surface – cave F2 hybrids were assessed for several morphological and behavioral phenotypes. There were significant differences found between pigmented and albino individuals, raising the question of a shared genetic basis for these traits. Oculocutaneous albinism 2 (oca2) is a notable contributor to albinism in many species, including A. mexicanus. Surface fish with CRISPR mutations at oca2 confirmed a contribution of oca2 in sleep loss within albino cavefish. Further, it was determined that oca2 is under selection and possibly has a pleiotropic function, which underlies the adaptive evolution of sleep loss and albinism.