Friday, October 24, 2014

Lapu-lapu DNA study reveals new data on threatened species

The mighty lapu-lapu (grouper) has been fingerprinted, revealing new and valuable information on one of the country's most expensive commodities.

The first genetic inventory of lapu-lapu was conducted by scientists at the Central Luzon State University (CLSU) using DNA fingerprinting and bar coding which characterized 27 species of commercially important lapu-lapu or groupers.

In genetics, DNA fingerprintings isolate and make images of sequences of DNA (deoxyribonucleic acid). DNA barcoding uses a short genetic marker in the DNA to identify it as belonging to a particular species.

The study was conducted by Simon Alcanta and Dr. Apolinario V. Yambot of CLSU's Biotechnology and Analytical Laboratory Project.

The biotechnology tool DNA bar coding made possible the identification of grouper specimens at the species-level with a high degree of confidence and efficiency. 

Previous studies were based only on morphology or the characterization of the form and structure and the specific structural features of lapu-lapu which may be inconclusive and may cause confusion on grouper taxonomy especially without a trained specialist.

Mr. Alcantara, the principal author, observes the DNA identification is generally challenging because of lapu-lapu's unpronounced and overlapping morphological characters. 

''In the Philippines, an updated, reliable and accurate inventory of this high value commercial groupers has not been carried out previously. Using molecular tools in the identification and inventory of fish species in the country is confined to few laboratories and experts in the country.''

Aside from reinforcing the classical methodology of grouper identification in the country, the pioneering study on molecular identification of Philippine groupers constitutes a significant contribution to the DNA barcode library of Philippine marine fishes and to the global barcode entries in general.

The information can be used when dealing with grouper taxonomy, biodiversity, stock assessment and trade.  The results also reveal the different localities where the grouper species can be possibly sourced out in the country for trade and aquaculture purposes. 

The initiative identified the highly diverse grouper population in the country with an average rate of 20 percent genetic distance within family, 15 percent within genus, and 0.68 percent within species.  Using a genetic marker, 94 bar codes were generated to identify and differentiate the 27 lapu-lapu species. Most of the identified species include groupers belonging to the large sea fish (Epinephelus), aquarium fish (Cephalopholis) and the species of leopard coral grouper, spotted coral grouper and black saddled coral grouper (Plectropomus). Slender grouper (Anyperodon leucogrammicus) and humpback grouper (Chromileptis altivelis) were also identified.

New genetic information for dothead rockcod (Cephalopholis microprion), blue-lined grouper (Cephalopholis polleni) and dot-dash grouper (Epinephelus poecilonotus) was not available in the GenBank database prior to the study. 

The GenBank is an annotated collection of all publicly available DNA sequences. This database is hosted by the National Center for Biotechnology Information in the United States to provide the international scientific community with up-to-date and comprehensive information on DNA sequences for research, trade, management and aquaculture.

Six of the identified grouper species are listed as vulnerable and near-threatened species in the International Union for the Conservation of Nature’s Red List of Threatened Species. As a tool for conservation ecology, the study signals the implementation of sustainable fisheries management regulation to protect threatened species.

In lapu-lapu, these include the black saddled coral grouper, humpback grouper and orange-spotted grouper (E. coioides), black marbled grouper (E. fuscoguttatus), Malabar grouper (E. malabaricus) and the leopard coral grouper. 

The study, supported by the Biotechnology Program of the Department of Agriculture. (SciencePhilippines)

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