Panmixia in Pocillopora verrucosa from South Africa

Marine Ecology Progress Series, 2014

PLoS ONE, 2013

Pocillopora damicornis (Linnaeus, 1758; Scleractinia, Pocilloporidae) has recently been found to comprise at least five distinct genetic lineages in Eastern Australia, some of which likely represent cryptic species. Due to similar and plastic gross morphology of these lineages, field identification is often difficult. Here we present a quick, cost effective genetic assay as well as three novel microsatellite markers that distinguish the two most common lineages found on the Great Barrier Reef. The assay is based on PCR amplification of two regions within the mitochondrial putative control region, which show consistent and easily identifiable fragment size differences for the two genetic lineages after Alu1 restriction enzyme digestion of the amplicons.

Molecular Ecology …, 2008

We report the development of 10 polymorphic molecular markers containing short tandem repeats in the cosmopolitan reef-building coral, Pocillopora damicornis, an important model species for coral health, physiology, ecology, and genetics. The availability of polymorphic DNA markers in P. damicornis can act as impetus for investigations into inheritance and population genetics, as well as novel investigations into host-symbiont ecology and evolution. Coral bleaching and gene flow studies performed with these markers can have direct conservation implications.

Coral Reefs, 1984

An electrophoretic study of genetic differentiation amongst local populations of the reef-coral Pocillopora damicornis was used to group coral heads into units defined as the area of effective dispersal of a clone, and termed "colonies". For reefs off southwestern Australia, colonies were usually under a few hundred metres in extent. Although most new recruits within a colony were derived asexually, sexually produced propagules acted to connect populations outside the boundaries of a colony. Such connections were weak, and allelic frequencies varied considerably over a few kilometres. The primary agent of genetic differentiation was suggested to be the small effective population size resulting from the asexual proliferation of a few genotypes at any site. The effective number of genotypes per colony was approximately six. Asexual reproduction appears also to limit gene flow and accentuate selection in this species.

Marine Ecology Progress Series, 1997

The widespread and morphologically variable coral Pocillopora damjcornis has been reported to exhlbit huge variation in Me-history traits (e.g. inode of reproduction, growth rate, longevity and dispersal) both locally and regionally throughout the Indo-Pacific Ocean. Dispersal may b e achieved by the settlement of sexually or asexually generated brooded planula larvae, by broadcast spawning or more locally through asexual fragmentation of large colonies. In the present study, we conducted a hierarchical survey of allozyme variation within and among reef-crest sites on 3 mid-shelf reefs separated by up to 1200 km on the Great Barrier Reef (GBR), Australia. Our objective was to use allozyme data ( 1 ) to quantify local and reglonal patterns of varlatlon in P, damicornis (along the northeastern coast of Australia), (2) to determine the relative contr~bution of sexual versus asexual production of planulae in P damicornis, and (3) to estimate levels of gene flow among adlacent sites (>5 km apart) and among reefs separated by 500 to 1200 km. High levels of genotypic dlvers~ty in our samples of P. darn~cornis imply that dispersive propagules in this species are produced sexually rather than asexually along the length of the GBR. Corals a t all sites displayed the same level of multi-locus genotypic diversity expected for randomly mating, sexually derived populations, and the majority of individual colonies possessed unique 7-locus genotypes. We also detected consistent deficits of heterozygotes within each collection (from 3 local sites on each of the 3 widely spaced reefs). This pattern is consistent with the predicted effects of sexual reproduction associated with some localised dispersal of gametes or larvae (although other explanations cannot be excluded). Furthermore, each reef was genetically subdivided, suggesting that larval recruitment was localised and that these populations are slightly inbred: hierarchical analysis of the standardised genetic variances (FsT) (estimated as Weir & Cockerham's 0) revealed that, although there was only moderate variation among all 9 sites (FST = 0.055 t 0.029), more variation was found among sites within reefs (F,, = 0.035 * 0.04 to 0.088 2 0.033) than among distant reefs = 0.008 * 0.014) This homogeneity of gene frequencies across widely separated reefs lmplles that reefs are connected by high levels of gene flow (.V,~m = 31) and that local popu-lat~ons of P. damlcornls separated by >l000 km can interbreed sufficiently to maintain a consistent sulte of life-history characters.

Frontiers in Marine Science, 2015

The Red Sea is the world's northernmost tropical sea. The 2000 km long, but narrow basin creates distinct environmental conditions along its latitudinal spread. The Red Sea displays a pronounced salinity gradient from 41 to 37 PSU (north to south) with an opposing temperature gradient from 21 to 27 • C in the north to 27-33.8 • C in the south. The Red Sea further displays a decreasing nutrient gradient from south to north that can also influence underwater light fields due to higher phytoplankton content and turbidity. Despite this strong variation in temperature, salinity, nutrients, and light conditions, the Red Sea supports large and diverse coral reef ecosystems along its nearly entire coastline. Only few studies have targeted whether these prevailing gradients affect genetic connectivity of reef organisms in the Red Sea. In this study, we sampled the abundant reef-building coral Pocillopora verrucosa from 10 reefs along a latitudinal gradient in the Red Sea covering an area of more than 850 km. We used nine Pocillopora microsatellite markers to assess the underlying population genetic structure and effective population size. To assure the exclusion of cryptic species, all analyzed specimens were chosen from a single mitochondrial lineage. Despite large distances between sampled regions covering pronounced, but smooth temperature and salinity gradients, no significant genetic population structure was found. Rather, our data indicate panmixia and considerable gene flow among regions. The absence of population subdivision driven by environmental factors and over large geographic distances suggests efficient larval dispersal and successful settlement of recruits from a wide range of reef sites. It also advocates, broadcast spawning as the main reproductive strategy of Pocillopora verrucosa in the Red Sea as reflected by the absence of clones in sampled colonies. These factors might explain the success of Pocillopora species throughout the Indo-Pacific and Arabian Seas.

Oceanography, 2013

Genetica, 2022

Correctly delimiting species and populations is a prerequisite for studies of connectivity, adaptation and conservation. Genomic data are particularly useful to test for species differentiation for organisms with few informative morphological characters or low discrimination of cytoplasmic markers, as in Scleractinians. Here we applied Restriction site Associated DNA sequencing (RADsequencing) to the study of species differentiation and genetic structure in populations of Pocillopora spp. from Oman and French Polynesia, with the objectives to test species hypotheses, and to study the genetic structure among sampling sites within species. We focused here on coral colonies morphologically similar to P. acuta (damicornis type β). We tested the impact of different filtering strategies on the stability of the results. The main genetic differentiation was observed between samples from Oman and French Polynesia. These samples corresponded to different previously defined primary species hypotheses (PSH), i.e. PSHs 12 and 13 in Oman, and PSH 5 in French Polynesia. In Oman, we did not observe any clear differentiation between the two putative species PSH 12 and 13, nor between sampling sites. In French Polynesia, where a single species hypothesis was studied, there was no differentiation between sites. Our analyses allowed the identification of clonal lineages in Oman and French Polynesia. The impact of clonality on genetic diversity is discussed in light of individual-based simulations.

Marine Biology, 2014

throughout its geographic range; comparison with results previously obtained for the congeneric species Pocillopora meandrina underlines the importance of life history traits in shaping the genetic structure of coral populations.

PLOS ONE, 2019

Scleractinia of the Maputaland reef complex (MRC) in South Africa exist at the margins of the Western Indian Ocean (WIO) coral distribution and are the only substantial hermatypic coral communities in South Africa. Pocillopora species occupy a conspicuous component of the MRC, and previous investigations identified three species of Pocillopora utilizing conventional taxonomy. Thus, our aims were four-fold: to elucidate Pocillopora species diversity using genetic techniques, primarily using species delimitation methods based on the ORF gene; to test for the presence of hybridisation within the Pocillopora community on the SouthWest margin of distribution in the Indian Ocean using two nuclear and two mitochondrial markers; to test the presence of cryptic species, using 13 microsatellite markers, finally, to elucidate the degree of genetic diversity within each Pocillopora species found and compare this to communities in lower latitudes. We illustrate taxonomic inconsistencies between these inventories and our phylogenetic data. The MRC harbours unique populations of Pocillopora, consisting of three species hypothetically co-occurring throughout the south WIO, namely: P. meandrina/P. eydouxi, commonly misidentified as P. verrucosa, P. verrucosa, sometimes correctly identified, but also commonly misidentified as P. damicornis sensu lato, and P. villosa, almost always misidentified as P. eydouxi. The hypothesis that hybrid swarms of Pocillopora occur in marginal environments such as the MRC was not supported, with low levels of introgressive hybridization reported instead. Analyses illustrate low genetic diversity at the species and population resolutions, suggesting a small founder population for each species. Nevertheless, these populations are demographically unique, exhibiting high levels of ITS2 haplotype endemism compared to higher latitude populations and the rest of the WIO. Pocillopora diversity on the MRC represents a unique assemblage and warrants further protection.