Validation of internal reference genes for gene expression analysis in Montipora digitata, Pocillopora damicornis and Acropora nasuta by quantitative real-time PCR

Abstract

Abstract The highest concentrations of Indo-Pacificreef coral species occur in the Coral Triangle (CT). A large part of the CT is bordering the edge of the Sunda Shelf, with the highest species richness to the north and east of the Sunda Shelf, including parts of Malaysia, Indonesia, the Philippines, Papua New Guinea, Timor Leste, and the Solomons. Within eastern Indonesia also differences in coral reef fauna can be observed, e.g. between Sulawesi and West Papua. There is no relation with Wallace’s Line or with Wallacea, the area in between the Sunda and Sahul shelves, which both relate to terrestrial biogeography. The west-east variation in marine species diversity can be explained hypothetically in four ways. The CT has more species because of (1) plate tectonics; (2) a higher species survival during the Last Glacial Maximum (LGM); (3) higher habitat variability, especially from near-shore (shallow, sheltered, murky water) to offshore (deep, ex-posed clear water); (4) inter-oceanic currents running in north-south direction between the Pacificand the Indian Ocean, such as the Indonesian Through Flow (ITF), pre-venting connections between west and east. Future re-search should give more insight in the relative im portance of these four factors and whether there are clear-cut lines of division or zones of transition with ever-changing species compositions.