The Moran Lab combines behavioral research with genomic technologies to understand the adaptive and mechanistic underpinnings of species diversification. We integrate experimental and computational approaches to test major evolutionary hypotheses in natural systems. Previous work has focused on two groups of North American stream fishes (darters and Mexican tetras).

Our overarching research goals include:

(1) Understanding how behavioral interactions between species (e.g., mating and fighting) promote the evolution of phenotypic and molecular divergence between and within species.

(2) Identifying features of genomic architecture that facilitate the evolution of reproductive barriers (i.e., traits that prevent hybrids from forming and/or reproducing) in the face of gene flow.

(3) Investigating the genetic basis of repeated evolution and determine how gene flow, de novo mutation, and standing genetic variation contribute to the convergent evolution of adaptive traits.

Biologists have long appreciated that mate choice and competition can promote diversification within species and lead to speciation. It is now clear that these interactions also commonly occur between species, with major ecological and evolutionary consequences. Selection to avoid interspecific mating (hybridization) can promote the evolution of mating traits through reproductive character displacement. Similarly, selection to avoid interspecific fighting can promote the evolution of competitive traits through agonistic character displacement. Character displacement can result in enhanced trait divergence between species in sympatry compared to allopatry and can play a key role in species diversification by favoring the evolution of behavioral isolation when closely related species co-occur. Recent work has demonstrated that character displacement may play an underappreciated role in driving species diversification at both micro- and macroevolutionary scales. Our work in darters asks how character displacement drives phenotypic and molecular evolution between and within species. To this end, we are interested in mating and aggressive interactions within and between species and patterns of genomic divergence among populations and species. New avenues of research in the lab include an investigation into the neurogenomic basis of species discrimination in these fishes using cutting edge genomic and functional tools.

Other ongoing work includes population genomic analyses off repeated adaption to caves in the Mexican tetra. In this species, ancestral surface populations have repeatedly adapted to harsh cave environments through evolution of the same suites traits, including enhancements to non-visual sensory systems, eye loss, albinism, and sleep loss. Our recent work has leveraged this system to investigate the ecological genomics of cave adaptation and to study the predictability and repeatability of molecular evolution.

1. Kellermeyer, R, Seidel, C, Redwine, WB, Moran, RL, Bertho, S, Ornelas-García, CP et al.. Long-term hybridization in a karst window reveals the genetic basis of eye loss in cavefish. bioRxiv. 2024; :. doi: 10.1101/2024.10.25.620266. PubMed PMID:39554031 PubMed Central PMC11565769.
2. Lloyd, E, Xia, F, Moore, K, Zertuche, C, Rastogi, A, Kozol, R et al.. Elevated DNA Damage without signs of aging in the short-sleeping Mexican Cavefish. bioRxiv. 2024; :. doi: 10.1101/2024.04.18.590174. PubMed PMID:38659770 PubMed Central PMC11042282.
3. Black, TN, Rastogi, A, Saegert, A, Dib, J, Moran, RL. Male recognition of conspecific female chemical cues in a diverse clade of freshwater fishes. J Fish Biol. 2024;104 (3):883-886. doi: 10.1111/jfb.15600. PubMed PMID:37906501 .
4. Garduño-Sánchez, M, Hernández-Lozano, J, Moran, RL, Miranda-Gamboa, R, Gross, JB, Rohner, N et al.. Phylogeographic relationships and morphological evolution between cave and surface Astyanax mexicanus populations (De Filippi 1853) (Actinopterygii, Characidae). Mol Ecol. 2023;32 (20):5626-5644. doi: 10.1111/mec.17128. PubMed PMID:37712324 .
5. Powers, AK, Hyacinthe, C, Riddle, MR, Kim, YK, Amaismeier, A, Thiel, K et al.. Genetic mapping of craniofacial traits in the Mexican tetra reveals loci associated with bite differences between cave and surface fish. BMC Ecol Evol. 2023;23 (1):41. doi: 10.1186/s12862-023-02149-3. PubMed PMID:37626324 PubMed Central PMC10463419.
6. Moran, RL, Richards, EJ, Ornelas-García, CP, Gross, JB, Donny, A, Wiese, J et al.. Selection-driven trait loss in independently evolved cavefish populations. Nat Commun. 2023;14 (1):2557. doi: 10.1038/s41467-023-37909-8. PubMed PMID:37137902 PubMed Central PMC10156726.
7. Moran, RL, Jaggard, JB, Roback, EY, Kenzior, A, Rohner, N, Kowalko, JE et al.. Hybridization underlies localized trait evolution in cavefish. iScience. 2022;25 (2):103778. doi: 10.1016/j.isci.2022.103778. PubMed PMID:35146393 PubMed Central PMC8819016.
8. O'Gorman, M, Thakur, S, Imrie, G, Moran, RL, Choy, S, Sifuentes-Romero, I et al.. Pleiotropic function of the oca2 gene underlies the evolution of sleep loss and albinism in cavefish. Curr Biol. 2021;31 (16):3694-3701.e4. doi: 10.1016/j.cub.2021.06.077. PubMed PMID:34293332 .
9. Chang, CH, Catchen, J, Moran, RL, Rivera-Colón, AG, Wang, YC, Fuller, RC et al.. Sequence Analysis and Ontogenetic Expression Patterns of Cone Opsin Genes in the Bluefin Killifish (Lucania goodei). J Hered. 2021;112 (4):357-366. doi: 10.1093/jhered/esab017. PubMed PMID:33837393 .
10. Warren, WC, Boggs, TE, Borowsky, R, Carlson, BM, Ferrufino, E, Gross, JB et al.. A chromosome-level genome of Astyanax mexicanus surface fish for comparing population-specific genetic differences contributing to trait evolution. Nat Commun. 2021;12 (1):1447. doi: 10.1038/s41467-021-21733-z. PubMed PMID:33664263 PubMed Central PMC7933363.