Meeting Abstract

P3.5  Wednesday, Jan. 6  Genetic Population Structure of Two Brittle Stars (Ophiocoma echinata and Amphipholis squamata) With Contrasting Life Histories ROJAS, M*; SCHIZAS, N.V.; University of Puerto Rico, Mayagüez monicarojasp@gmail.com

Knowledge of the genetic population structure of species is required for sustainable management plans, since changes in population dynamics and demographics have direct consequences on the exploitability and sustainability of species. Echinoderms display a wide array of life histories, which can have a profound effect in the dispersal potential and population structure of species. The brittle stars Ophiocoma echinata and Amphipholis squamata are commonly found in the shallow waters of the Caribbean Sea. The two species exhibit differing modes of development: O. echinata is a spawning species having asynchronous breeding cycles and A. squamata is a brooding species, viviparous and self-fertilizing hermaphrodite. Their overlapping geographic range offers the potential to compare their genetic population structure as generally, brooders are expected to exhibit higher population subdivision than spawners. Mitochondrial (16S) and ribosomal nuclear DNA sequences (ITS-1) were recovered from eight populations of O. echinata and A. squamata around the Caribbean. Preliminary results indicate that the spawning O. echinata harbors high levels of genetic variability in the mitochondrial gene 16S (115 specimens, 33 haplotypes). There is significant population structure (FST = 0.10259; P = 0.00978) among specimens distributed in the eastern Caribbean and Panama. Pairwise FST comparisons indicate that there is a genetic break between eastern and western Caribbean. Samples of A. squamata are currently processed from Caribbean localities to compare the effect of different life histories in the population structure of species.