By Valerie Perini

Reef-building corals are a globally important, albiet globally threatened group of organisms. Efforts to better understand how these essential foundation species have evolved and radiated throughout the world’s tropical oceans have identified fundamental disagreements among a major coral lineage known as Pocillopora corals. A new publication by recent Northeastern PhD recipient David Combosch and MSC Associate Professor Steve Vollmer provides evidence that these genetic discrepancies may result from hybridization among distinct Pocillopora lineages.

In the study, recently published in the journal Molecular Phylogenetics and Evolution, Combosch and Vollmer used a powerful genomics technique called Restriction-site Associated DNA Sequencing (RAD-Seq), to conduct phylogenetic comparisons within and between populations of three common Pocillopora species in the Tropical Eastern Pacific and Central Pacific.

Results indicate that the important and widely distributed Indo-Pacific reef-builder Pocilloproa damicornis contains at least three distinct genetic lineages. In contrast, Pocillopora species in the Eastern Pacific hybridize and may exchange large parts of their genomes via one-way introgressive hybridization, as confirmed by genome-scans of hybrid specimen. These results provide insight into the mechanisms by which coral populations obtain new genetic information that may be used to adapt to challenging environmental conditions, allowing researchers to better understand the evolutionary biology of these sensitive organisms.