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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.
  • Transcriptome-derived SNP markers for population assignment of sandfish, Holothuria (Metriatyla) scabra
    Ordoñez, June F.; Ravago-Gotanco, Rachel (Elsevier, 2024-01-30)
    The sandfish, Holothuria scabra is a commercially important fishery and aquaculture species contributing to the high-value sea cucumber industry. Overexploited across many areas throughout its distributional range, natural populations are considered in decline. Accurate genetic assignment to population of origin is becoming increasingly important for genetics-based marine fisheries management and monitoring, especially for species experiencing depletion of natural stocks and decline in fisheries productivity due to overfishing and illegal, unreported, and unregulated (IUU) fishing. Initiatives for genetics-based applications on economically important seafood such as H. scabra have been limited by the lack of comprehensive genome or transcriptome resources. The present study developed and evaluated the use of gene-associated single nucleotide polymorphism (SNP) markers to assign sandfish to three locations in the Philippines, in the proximity of existing and emerging hatchery production centers. In silico SNP discovery pipeline using pooled RNA-Seq libraries and medium-throughput genotyping approach generated a dataset comprising 115 individuals genotyped at 88 SNPs. Population assignment using machine-learning analysis and Bayesian approach revealed that the 88 transcriptome-derived SNPs allowed the assignment of sandfish individuals to population of origin, with an overall assignment accuracy of >80%. The novel SNPs developed could find their utility in facilitating the development of geographic traceability tools applicable in the context of sandfish aquaculture, fisheries management and conservation.