11th ICRS Abstract book - Nova Southeastern University
11th ICRS Abstract book - Nova Southeastern University
11th ICRS Abstract book - Nova Southeastern University
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Oral Mini-Symposium 26: Biodiversity and Diversification of Reef Organisms<br />
26-50<br />
Mitochondrial Gene Variation And The Search For An Octocoral Barcode<br />
Catherine MCFADDEN* 1 , Andrew NEVAREZ 2<br />
1 Biology, Harvey Mudd College, Claremont, CA, 2 Harvey Mudd College, Claremont, CA<br />
Slow rates of mitochondrial gene evolution have hindered the development of speciesspecific<br />
genetic markers, or DNA barcodes, in the anthozoan cnidarians. Previous<br />
studies of various mitochondrial gene regions have concluded that levels of mtDNA<br />
variation simply are not sufficient to reliably distinguish closely related species of<br />
anthozoans. These results have been extrapolated to predict that the 5' fragment of<br />
cytochrome oxidase I (COI), proposed for use as a universal species-specific marker for<br />
the “Barcode of Life” initiative, will not differentiate all anthozoan species. Levels of<br />
sequence variation in this approximately 640 bp gene region have never been explicitly<br />
quantified in the anthozoan subclass Octocorallia, however, in part because the universal<br />
“Folmer” PCR primers do not amplify octocoral COI. Using octocoral-specific PCR<br />
primers, we examined intra- and interspecific variation in the 5' COI region in a genus of<br />
soft corals for which species boundaries have previously been confirmed using allozymes<br />
and other genetic markers. Most, but not all, pairs of sister taxa could be differentiated<br />
on the basis of unique substitutions in COI, but levels of intraspecific variation were<br />
often comparable to or greater than the observed interspecific differences. Two other<br />
mitochondrial gene regions, the COI-COII intergenic spacer and the 5' fragment of the<br />
octocoral-specific mitochondrial mutS homolog (msh1), had levels of intra- and<br />
interspecific variation comparable to the 5' COI fragment. A barcode that combined all<br />
three of these gene regions (~1500 bp total) had increased species-specificity relative to<br />
COI alone, but still lacked sufficient variation to distinguish all species pairs<br />
unequivocably. We conclude that COI is an adequate genus- and clade-specific barcode<br />
for octocorals, but even in combination with other equally variable mtDNA regions it<br />
lacks sufficient variation to be a reliable species-specific marker.<br />
26-51<br />
Phylogenetic Analysis Of The Caribbean Genera Eunicea And Plexaura<br />
(Octocorallia)<br />
Carlos PRADA* 1 , Nikolaos SCHIZAS 2<br />
1 Marine Sciences, <strong>University</strong> of Puerto Rico, Mayaguez, Lajas, Puerto Rico, 2 Marine<br />
Sciences, Universitry of Puerto Rico, Lajas, Puerto Rico<br />
Shallow water octocorals are conspicuously found in Caribbean reefs, yet aspects of their<br />
basic biology and systematics remain uncertain. Taxonomic work has traditionally relied<br />
on morphological features, but often some of these characters are inconclusive or not<br />
readily observed, introducing ambiguities in identification keys. Extensive phenotypic<br />
plasticity further complicates the correct species identification. Eunicea is the most<br />
diverse octocoral genus in Caribbean reefs and species of this genus are separated by<br />
shape and size of calices and sclerites. These characters are highly plastic, generating<br />
non-discrete patterns which are necessary to correctly identify species. Here, a<br />
phylogenetic reconstruction of the genera Plexaura and Eunicea is presented, using<br />
mitochondrial and recently developed nuclear markers. The molecular evolution of both<br />
genomes is compared and the suitability of these markers to address species boundaries<br />
and population level questions is explored. An earlier taxonomic hypothesis regarding<br />
the non-monophyletic status of Eunicea based on the shape of external clubs is<br />
phylogenetically tested. Discrete forms of Plexaura homomalla (i.e., kukenthali and<br />
homomalla) are examined to determine their taxonomic status. An example is provided<br />
where two distinct genetic lineages are present within the conspicuous, well studied<br />
Eunicea flexuosa.<br />
26-52<br />
Total Evidence Molecular Phylogenetic Analysis Of Octocorallia (Cnidaria: Anthozoa)<br />
Yields A Replete Evolutionary Hypothesis And Identifies Potential Species-Level Markers<br />
Jaret BILEWITCH* 1 , Kathryn COATES 2<br />
1 Dept. of Geology, <strong>University</strong> at Buffalo, Buffalo, NY, 2 Dept. of Conservation Services,<br />
Bermuda Ministry of the Environment, Flatts, Bermuda<br />
Recent studies seeking to elucidate the species-level systematics of octocorals have been<br />
hindered by low variability in the mitochondrial genome. Although many multi-locus datasets<br />
are available in GenBank, including some complete sequences of mitochondrial genomes, a<br />
comprehensive analysis using several (or all) of them has not been attempted. We sought to<br />
consolidate the findings of these studies into a single phylogenetic hypothesis. All existing<br />
mitochondrial sequences of octocorals available in GenBank were collated, along with several<br />
large nuclear datasets, and the combined alignment was analyzed in a ‘total evidence’ approach.<br />
Application of both parsimonious and model-based phylogenetic criteria yielded results that<br />
were largely concordant with the hypotheses originally associated with individual datasets and<br />
also allowed comparison to taxa from disparate datasets. The resulting comprehensive<br />
phylogeny also summarizes the efforts of researchers to date and indicates several areas where<br />
future attempts may be directed. While the focus of many recent studies has been in locating<br />
novel one- or two-locus species-level markers, we find that the existing data, when analyzed<br />
collectively is ample to address alpha-taxonomic questions, albeit only for species with<br />
sufficient numbers of informative characters. Furthermore, our total evidence analysis suggests<br />
that several species-level markers may have already been overlooked due to insufficient taxon<br />
sampling at the time they were obtained. We advocate that future attempts be analyzed in<br />
combination with previous datasets in order to maximize the information content of<br />
phylogenetic hypotheses and maintain an inclusive and contemporary synthesis of octocoral<br />
systematics.<br />
26-53<br />
Molecular Recognition Of Zooxanthella Clade G in Caribbean Excavating Sponges<br />
(Cliona Spp.)<br />
Camila GRANADOS* 1 , Carolina CAMARGO 1 , Dairo ESCOBAR 1 , Sven ZEA 2 , Juan A<br />
SÁNCHEZ 1<br />
1 Laboratorio de Biología Molecular Marina, BIOMMAR, Departamento de Ciencias<br />
Biológicas, Universidad de los Andes, Bogotá, Colombia, 2 Departamento de Biología y Centro<br />
de Estudios en Ciencias del Mar - CECIMAR, Universidad Nacional de Colombia, Santa Marta,<br />
Colombia<br />
Zooxanthellae (Symbiodinium) are symbiotic dinoflagellates distributed in tropical and<br />
subtropical reefs. Eight major clades of zooxanthellae, symbiotic to different organisms such as<br />
cnidarians, sponges, and foraminifera, have been found (termed A–H) using molecular<br />
techniques. Among them, sponges are one of the least studied for this symbiotic relationship.<br />
They are present and abundant in most marine-ecosystems. Besides participating as important<br />
bioeroders of the reef framework, some of them engage symbiosis with zooxanthella. Although<br />
they are potentially threatened by the same environmental factors affecting reef-building corals<br />
they seem to be less affected. In this study, five sponge species were surveyed (Cliona<br />
caribbaea, C. tenuis, C. varians, C. aprica, C. laticavicola) in order to characterize the<br />
Symbiodinium lineages using molecular markers (SSU-rDNA-18S, ITS2, cp23S-rDNA, and<br />
mtDNA) and phylogenetic approaches. Three different sites were sampled in Colombia, which<br />
included Southern and Southwestern Caribbean reefs. All specimens collected at all sites<br />
contained Symbiodinium clades-A, B, & G determined by the molecular markers. Inferred<br />
phylogenies were concordant with all the clades described. Findings of clades-A&B fitted with<br />
the general pattern of the province, where clade-B is almost endemic and types such as A4<br />
engage symbiosis with many species. A new finding was the presence of Symbiodinium clade-<br />
G. It is found in a wide range of invertebrates but they seem restricted to the Western Pacific.<br />
Particularly intriguing, foraminifera that have clade-G in the Indopacific have clade-C in the<br />
Eastern Pacific and F or H in the Caribbean. Given that this is the first time clade-G is reported<br />
at any Atlantic location, it arises the question on the lineage origin: 1) due to differences in the<br />
primordial origin of the symbiosis between sponges and corals or 2) there is a phylogeneticrelic<br />
through common ancestors of sponges clades, latter being tested with the host sponge<br />
phylogeny.<br />
254