Meeting Abstract
Corals with long sexual generation times are typically assumed to be incapable of adapting over short ecological time scales. However, old coral colonies that have experienced many rounds of cell division may accumulate considerable numbers of somatic mutations over the course of their lifetimes. It has been hypothesized that these mutant cell-lineages can contribute heritable genetic variation, which can be acted upon by selection in corals. We are investigating this hypothesis with innovative genotyping methods based on next-generation sequencing technologies. Two massive colonies of Orbicella (Montastrea) faveolata, estimated to be more than 300 years old, were sampled from the Flower Garden Banks in the Gulf of Mexico. Replicate samples of adult tissue and gametes were taken from opposite sides of each colony, as the greatest numbers of cell divisions are expected to separate these locations. All samples were genotyped using a modified 2b-RAD protocol that is capable of discarding PCR duplicates and thus measure the SNP frequencies with better precision. With these data we will identify new somatic mutations and estimate the frequency with which they accumulate. Moreover, we will determine whether these mutations are passed onto the next generation, thus contributing to genetic variation in the species. This project is the first experimental investigation into the impact of somatic mutation on genetic diversity in an ecologically important species. Results of this work have implications for models of adaptation and conservation in corals as well as other long-lived colonial organisms.
