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National Committee on Marine Sciences (NCMS)

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    Genetic diversity and population connectivity of the greenblotch parrotfish (Scarus quoyi Valenciennes, 1840) within southern Mindanao inferred from mitochondrial 16S rRNA
    Labrador, Kevin; Fortaleza, Maybelle; Cabasan, Joey; Elumba, Merlene; Nañola, Cleto (Science and Technology Information Institute, 2022-10-03)
    A genetic assessment was done on the greenblotch parrotfish (Scarus quoyi Valenciennes, 1840) in three bays within southern Mindanao, Philippines. Mitochondrial 16S rRNA recovered 12 haplotypes, one of which was dominant in all sites. Despite the reported phenotypic variation from previous assessments, there was neither evidence of genetic structure (global Φst = 0.012, p = 0.13) nor isolation by distance (r = 0.05, p = 0.50). Genetic diversity was also low (Hglobal = 0.472; πglobal = 0.13%), with ~ 77% of haplotype diversity accounted for with just 69 samples. While connectivity suggests continuous larval exchange within southern Mindanao owing to the species’ high dispersal potential, low genetic diversity implies reduced effective population size, probably due to recent bottlenecks (e.g. overfishing, habitat destruction). Although this study provides baseline genetic information on the local population, inferences are considerably limited by the genetic marker used and the spatial scale under investigation. A thorough understanding of the population will be possible if the entire habitat range of the species is assessed using markers with high resolving power, such as the hypervariable mitochondrial control region, microsatellites, or genome-wide single nucleotide polymorphisms (SNPs).
    This project was funded by the DOST-PCAARRD (Department of Science and Technology–Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development) through the projects titled “DNA Barcoding and Genetic Diversity of Selected Marine Fishes along the North Bifurcation of the North Equatorial Current (NEC)” and “DNA Barcoding of Selected Marine Fishes in Davao and Sulu Archipelago (MINDA).” Sample collection was covered by the DARETO (Discovery-Applied Research and Extension for Trans/Inter-disciplinary Opportunities) research grant under CHED (Commission on Higher Education) through the project entitled “Bioeconomic Assessment and Modelling of Reef Fisheries and Sustainable Harvest Project”. We would like to thank Junissa M. Consuegra, Joemarie J. Lanutan, and Jodi Eugenia Lourdes F. del Fierro for their assistance in sample collection and laboratory work.
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    Pseudocryptic diversity and species boundaries in the sea cucumber Stichopus cf. horrens (Echinodermata: Stichopodidae) revealed by mitochondrial and microsatellite markers
    Lizano, Apollo Marco D.; Kim, Kenneth M.; Juinio-Meñez, Marie Antonette; Ravago-Gotanco, Rachel (Nature Research, 2024)
    Morphologically cryptic and pseudo-cryptic species pose a challenge to taxonomic identification and assessments of species diversity and distributions. Such is the case for the sea cucumber Stichopus horrens, commonly confused with Stichopus monotuberculatus. Here, we used mitochondrial cytochrome oxidase subunit I (COI) and microsatellite markers to examine genetic diversity in Stichopus cf. horrens throughout the Philippine archipelago, to aid species identification and clarify species boundaries. Phylogenetic analysis reveals two recently diverged COI lineages (Clade A and Clade B; c. 1.35–2.54 Mya) corresponding to sequence records for specimens identified as S. monotuberculatus and S. horrens, respectively. Microsatellite markers reveal two significantly differentiated genotype clusters broadly concordant with COI lineages (Cluster 1, Cluster 2). A small proportion of individuals were identified as later-generation hybrids indicating limited contemporary gene flow between genotype clusters, thus confirming species boundaries. Morphological differences in papillae distribution and form are observed for the two species, however tack-like spicules from the dorsal papillae are not a reliable diagnostic character. An additional putative cryptic species was detected within Clade B-Cluster 2 specimens warranting further examination. We propose that these lineages revealed by COI and genotype data be referred to as Stichopus cf. horrens species complex. © The Author(s) 2024.