Genetic barcoding of commercial Bêche-de-mer species (Echinodermata: Holothuroidea)

Date: Dec 29, 2009

Pub: Molecular Ecology Resources. 10(4) 634-646

Author(s): Uthicke, S., Byrne, M., & Conand, C.

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Abstract:

There are more than 47 species of holothurians used for beˆche-de-mer production, many of which are locally overfished. With three exceptions, all beˆche-de-mer species are Aspidochirotida and species identification of many of these is difficult. We analysed available genetic information and newly generated sequences to determine if genetic barcoding with the mitochondrial COI gene can be used to identify beˆche-de-mer species. Although genetic data were available for 50% of beˆche-de-mer species, sufficient information and within-species replication were only available for six species. We generated 96 new COI sequences extending the existing database to cover most common species. COI unambiguously identified most beˆche-de-mer species providing a genetic barcode for the identification of known species. In addition, conspecific (1.3%) variation and congeneric (16.9%) divergence were well separated (‘barcoding-gap’) albeit with a small overlap, which may lead to some error if genetic sampling alone was applied for species discovery. In addition to identification of adults, COI sequences were useful to identify juveniles that are often morphologically different. Sequence data showed that large (deep) and small (shallow) morphotypes of Holothuria atra are the same species, but suggested potential cryptic species within this taxon. For beˆchede-mer, the COI barcode proved useful in species clarification and discovery, but further genetic and taxonomic work is essential for several species. Some beˆche-de-mer clades were problematic with morphologically disparate specimens sharing the same barcode. Our study indicated the presence of undescribed species (Bohadschia sp.) and species that constitute separate species in the Indian and Pacific Ocean (e.g. Holothuria fuscogilva).