Molecular diversity of benthic ctenophores (Coeloplanidae)

Coeloplanidae, the largest family of benthic ctenophores, comprises 33 species, all described based on traditional morphological characteristics, such as coloration, length, and number of aboral papillae, which are highly variable and can be affected by fixation methods and environmental conditions. Thus, there is a need for reliable genetic markers to complement the morphological identifications at the species level. Here, we analyzed 95 specimens from 11 morphologically distinct species of benthic ctenophores from the Red Sea and Sulu Sea, and tested selected regions of four genetic markers (ITS1, 18S rRNA, 28S rRNA and COI) for their ability to differentiate between species. We show that the barcoding region of the mitochondrial gene cytochrome oxidase subunit I (COI) is highly variable among species of Coeloplanidae, and effectively discriminates between species in this family. The average Kimura-2-parameter (K2P) distance between clades was 10%, while intraspecific variation was ~30 times lower (0.36%). COI based phylogeny supported the delineation of four recently described new species from the Red Sea. The other nuclear markers tested were found to be too conserved in order to separate between species. We conclude that COI is a potential molecular barcode for the family Coeloplanidae and suggest testing it in pelagic ctenophores

Development of Gene Expression Markers of Acute Heat-Light Stress in Reef-Building Corals of the Genus Porites

Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide

Molecular diversity of benthic ctenophores (Coeloplanidae)

Coeloplanidae, the largest family of benthic ctenophores, comprises 33 species, all described based on traditional morphological characteristics, such as coloration, length, and number of aboral papillae, which are highly variable and can be affected by fixation methods and environmental conditions. Thus, there is a need for reliable genetic markers to complement the morphological identifications at the species level. Here, we analyzed 95 specimens from 11 morphologically distinct species of benthic ctenophores from the Red Sea and Sulu Sea, and tested selected regions of four genetic markers (ITS1, 18S rRNA, 28S rRNA and COI) for their ability to differentiate between species. We show that the barcoding region of the mitochondrial gene cytochrome oxidase subunit I (COI) is highly variable among species of Coeloplanidae, and effectively discriminates between species in this family. The average Kimura-2-parameter (K2P) distance between clades was 10%, while intraspecific variation was ~30 times lower (0.36%). COI based phylogeny supported the delineation of four recently described new species from the Red Sea. The other nuclear markers tested were found to be too conserved in order to separate between species. We conclude that COI is a potential molecular barcode for the family Coeloplanidae and suggest testing it in pelagic ctenophores

Molecular diversity of benthic ctenophores (Coeloplanidae)

Coeloplanidae, the largest family of benthic ctenophores, comprises 33 species, all described based on traditional morphological characteristics, such as coloration, length, and number of aboral papillae, which are highly variable and can be affected by fixation methods and environmental conditions. Thus, there is a need for reliable genetic markers to complement the morphological identifications at the species level. Here, we analyzed 95 specimens from 11 morphologically distinct species of benthic ctenophores from the Red Sea and Sulu Sea, and tested selected regions of four genetic markers (ITS1, 18S rRNA, 28S rRNA and COI) for their ability to differentiate between species. We show that the barcoding region of the mitochondrial gene cytochrome oxidase subunit I (COI) is highly variable among species of Coeloplanidae, and effectively discriminates between species in this family. The average Kimura-2-parameter (K2P) distance between clades was 10%, while intraspecific variation was ~30 times lower (0.36%). COI based phylogeny supported the delineation of four recently described new species from the Red Sea. The other nuclear markers tested were found to be too conserved in order to separate between species. We conclude that COI is a potential molecular barcode for the family Coeloplanidae and suggest testing it in pelagic ctenophores

Development of gene expression markers of acute heat-light stress in reef-building corals of the genus porites

Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide.National Science Foundation grant DEB-1054766 to MVM; Title V-Graduate programs/ELITE Graduate program: Event Travel Request program to LBS and JAH; Environmental Protection Agency Greater Research Opportunity Graduate Fellowship to KAK (MA-91697601); WIOMSA MARG III to PHM and RB; Aharon Katzir-Katchalsky Student Travel Fellowships and Anat Krauskopf Fund Travel Award to AA; NSF IOS-0747205 and funding from the University of Mississippi ORSP to TLG; Grants from both the National Science Council and Academia Sinica, Taiwan to KS; NSF GRF to RNS; Natural Environmental Research Council (NERC) studentship to CVP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript