O'Gorman, Morgan

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.