11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 13: Evolution and Conservation of Coral Reef Ecosystems
13-10
Local Interspecific Hybridization And Restricted Transpacific Gene Flow in
Tropical Eastern Pacific pocillopora
David J. COMBOSCH* 1,2 , Hector M. GUZMAN 2 , Helmut SCHUHMACHER 3 , Steve
V. VOLLMER 1,2
1 Biology, Northeastern University, Nahant, MA, 2 Smithsonian Tropical Research
Institute, Balboa, Panama, 3 Biology and Geography, University Duisburg-Essen, Essen,
Germany
Coral reefs in the Tropical Eastern Pacific (TEP) are among the most isolated in the
world. This isolation has leaded to relatively low species diversity but high regional
endemism. The dominant reef-building corals in the TEP are the Pocillopora corals, a
ubiquitous Indo-Pacific genus commonly regarded as inferior reef-builder. In addition to
being the dominant corals in the TEP, the Pocilloporids have undergone a reproductive
shift from internal larvae brooding throughout most of their Indo-Pacific range to free
gamete spawning in the TEP.
Using genetic data from the Internal Transcribed Spacer Regions (ITS) of the nuclear
ribosomal DNA gene cluster, we show here that this apparent reproductive shift coincides
with inter-specific hybridization among TEP Pocillopora species. We document a pattern
of one-way gene flow into the main TEP reef builder P. damicornis from one or both of
its TEP congeners –P. eydouxi and P. elegans. Strong population genetic differences
within P. damicornis further indicate that transpacific gene flow between the Central and
Eastern Pacific is rare (φct = 0.419). These results suggest that Eastern Pacific corals
exist in relative isolation from their Central Pacific counterparts, interact with each other
differently via hybridization, and thus must be protected for their evolutionary
uniqueness.
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