The Martin Fish Speciation lab is broadly interested in the origins of biodiversity. Our research centers on the rapid evolution of new fish species with novel ecology in relatively simple tropical ecosystems (salt lakes, volcanic craters). We integrate a variety of approaches including large-scale field experiments, population genomics, quantitative and functional genetics, phylogenetic comparative methods, natural history observations, functional morphology, and behavioral ecology. By mapping the complex relationships between genotype, phenotype, performance, fitness, and environment, we hope to gain a predictive understanding of the processes driving adaptive diversification.
We are currently developing three case studies of adaptive radiation: 1) Caribbean pupfishes, which exhibit remarkably localized adaptive radiations of trophic specialists in the Bahamas and Yucatan, 2) Cameroon crater lake cichlids, famous as putative examples of sympatric speciation, and 3) Death Valley pupfishes, critically endangered and highly managed desert fishes. Common themes in our work include 1) the ecological and hybrid swarm origins of adaptive radiation, 2) mechanisms driving this process on the fitness landscape, and 3) the evolution of novelty. Lab members are encouraged to pursue both field and laboratory studies of tropical fish systems because they present such a vast, diverse, and poorly studied view of vertebrate history.
Poelstra JW, Richards EJ, Martin CH. 2018. Speciation in sympatry with ongoing secondary gene flow and a potential olfactory trigger in a radiation of Cameroon cichlids. Molecular Ecology. Early view.
Richards EJ, Poelstra JW, Martin CH. 2018. Don't throw out the sympatric speciation with the crater lake water: fine-scale investigation of introgression provides equivocal support for causal role of secondary gene flow in one of the clearest examples of sympatric speciation. Evolution Letters. 2:524-540.
McGirr JA, Martin CH. 2018. Parallel evolution of gene expression between trophic specialists despite divergent genotypes and morphologies. Evolution Letters. 2:62-75.
Richards EJ, Martin CH. 2017. Adaptive introgression from distant Caribbean islands contributed to the diversification of a microendemic radiation of trophic specialist pupfishes. PLOS Genetics. 13:e1006919.
Martin CH, Erickson PA, Miller CT. 2017. The genetic architecture of novel trophic specialists: higher effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation. Molecular Ecology. 26:624-638.
McGirr JA, Martin CH. 2017. Novel candidate genes underlying extreme trophic specialization in Caribbean pupfishes. Molecular Biology and Evolution. 34:873-888.
Martin CH. 2016. The cryptic origins of evolutionary novelty: 1,000-fold-faster trophic diversification rates without increased ecological opportunity or hybrid swarm. Evolution 70:2504-2519.
Martin CH. 2016. Context dependence in complex adaptive landscapes: frequency and trait‐dependent selection surfaces within an adaptive radiation of Caribbean pupfishes. Evolution 70:1265-1282.
Martin CH, Crawford JE, Turner BJ, Simons LH. 2016. Diabolical survival in Death Valley: recent pupfish colonization, gene flow, and genetic assimilation in the smallest species range on earth. Proceedings of the Royal Society B. 283:23-34.
Martin CH, Cutler JS, Friel JP, Dening Touokong C, Coop G, Wainwright PC. 2015. Complex histories of repeated gene flow in Cameroon crater lake cichlids cast doubt on one of the clearest examples of sympatric speciation. Evolution 69:1406-1422.
Martin CH, Wainwright PC. 2013. Multiple fitness peaks on the adaptive landscape drive adaptive radiation in the wild. Science. 339:208-211.
Martin CH, Wainwright PC. 2011. Trophic novelty is linked to exceptional rates of morphological diversification in two adaptive radiations of Cyprinodon pupfishes. Evolution. 65:2197-2212.