SHEARER, Tonya L; COFFROTH, Mary Alice; University at Buffalo; University at Buffalo: Population structure and gene flow of Caribbean scleractinian corals as determined by microsatellite markers.

Investigations of gene flow and genetic structure of scleractinian coral populations have commonly utilized analyses of allozyme markers that reveal only a limited amount of the total genetic variation within a species. Highly polymorphic loci such as microsatellite markers provide a more highly resolved signal due to the high levels of variability relative to that observed in allozymes. Microsatellite markers, developed for the Caribbean scleractinian corals, Porites astreoides and Montastraea cavernosa, were used to determine gene flow and genetic structure of populations from Bermuda, the Florida Keys reef tract, the Bahamas, the Flower Garden Banks, Belize and Mexico. Levels of genetic structure were investigated within reefs (shallow versus deep), among reefs within a geographic location and among geographic locations to assess local and distant genetic exchange. Levels of genetic connectivity among reefs may differ between the two study species due to differences in reproductive mode (brooder and broadcaster, respectively) and/or larval dispersal capabilities. In addition to revealing historical genetic exchange as expressed in adults, the genetic signal of juveniles and new recruits were used to infer recent gene flow patterns and determine the dependence of local populations on distant populations as a source of new coral larvae.