Meeting Abstract

96.5  Monday, Jan. 6 14:30  Genetic signatures of ecological speciation in a coral-associated nudibranch FRITTS-PENNIMAN, AL*; MAHARDIKA, GN; BARBER, PH; Univ. of California, Los Angeles; Udayana Univ., Denpasar, Bali, Indonesia; Univ. of California, Los Angeles afrittspenniman@ucla.edu

In marine environments there are insufficient geographic barriers to attribute the great diversity of species to vicariance. However, coral reefs provide many opportunities for diversification through ecological niche specialization. For example, corals often host other invertebrates and fishes in mutualistic or parasitic relationships. The evolution of new, or more specific associations between corals and other reef organisms may lead to the creation of new species. Gene flow among populations found on different hosts may occur, but strong selection imposed by host species characteristics has the potential to reduce gene flow to the point of speciation. Previous work on Phestilla nudibranchs suggests that speciation may have occurred as a result of switching to different coral host genera. However, it remains unclear whether Phestilla species that are limited to a single host genus are diverging at the population level based on host species. I am examining how geography and coral host influence genetic divergence among specimens of Phestilla sibogae and Phestilla minor collected from locations spanning the Coral Triangle in the Indo-Pacific Ocean. Preliminary results reveal cryptic species and ongoing divergence associated with both geography and coral host in Phestilla minor but not in Phestilla sibogae. The development of single nucleotide polymorphism (SNP) markers is underway to detect host-driven adaptive genomic divergence, and ultimately identify which genes may be involved in speciation.