Hybridization underlies localized trait evolution in cavefish
Rachel L. Moran,
James B. Jaggard,
Emma Y. Roback,
Alexander Kenzior,
Nicolas Rohner,
Johanna E. Kowalko,
Claudia Patricia Ornelas-García,
Suzanne E. McGaugh,
Alex C. Keene
Affiliations
Rachel L. Moran
Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
James B. Jaggard
Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
Emma Y. Roback
Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
Alexander Kenzior
Stowers Institute for Medical Research, Kansas City, MO, USA
Nicolas Rohner
Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Molecular & Integrative Physiology, KU Medical Center, Kansas City, KS, USA
Johanna E. Kowalko
Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA; Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL USA
Claudia Patricia Ornelas-García
Departamento de Zoología, Instituto de Biología, Universidad Autónoma de México, Mexico City CP 04510, Mexico
Suzanne E. McGaugh
Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
Alex C. Keene
Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA; Department of Biology, Texas A&M University, College Station, TX 77843, USA; Corresponding author
Summary: Introgressive hybridization may play an integral role in local adaptation and speciation (Taylor and Larson, 2019). In the Mexican tetra Astyanax mexicanus, cave populations have repeatedly evolved traits including eye loss, sleep loss, and albinism. Of the 30 caves inhabited by A. mexicanus, Chica cave is unique because it contains multiple pools inhabited by putative hybrids between surface and cave populations (Mitchell et al., 1977), providing an opportunity to investigate the impact of hybridization on complex trait evolution. We show that hybridization between cave and surface populations may contribute to localized variation in traits associated with cave evolution, including pigmentation, eye development, and sleep. We also uncover an example of convergent evolution in a circadian clock gene in multiple cavefish lineages and burrowing mammals, suggesting a shared genetic mechanism underlying circadian disruption in subterranean vertebrates. Our results provide insight into the role of hybridization in facilitating phenotypic evolution.
