Advances in DNA Barcoding of Toxic Marine Organisms

Abstract

There are more than 200,000 marine species worldwide. These include many important economic species, such as large yellow croaker, ribbonfish, tuna, and salmon, but also many potentially toxic species, such as blue-green algae, diatoms, cnidarians, ctenophores, Nassarius spp., and pufferfish. However, some edible and toxic species may look similar, and the correct identification of marine species is thus a major issue. The failure of traditional classification methods in certain species has promoted the use of DNA barcoding, which uses short, standard DNA fragments to assist with species identification. In this review, we summarize recent advances in DNA barcoding of toxic marine species such as jellyfish and pufferfish, using genes including cytochrome oxidase I gene (COI), cytochrome b gene (cytb), 16S rDNA, internal transcribed spacer (ITS), and Ribulose-1,5-bisphosphate carboxylase oxygenase gene (rbcL). We also discuss the application of this technique for improving the identification of marine species. The use of DNA barcoding can benefit the studies of biological diversity, biogeography, food safety, and the detection of both invasive and new species. However, the technique has limitations, particularly for the analysis of complex objects and the selection of standard DNA barcodes. The development of high-throughput methods may offer solutions to some of these issues.

Keywords: food safety; molecular identification; seafood safety; toxic algae.

Figure 1

Histogram of marine species’ barcoding rates. The marine species’ barcoding rates were calculated using the data in Table 1. The percentages of the abscissa indicate the percentage of the number of species, and the percentage of the ordinate indicates the frequency of the barcoding rate.

Figure 2

Number of marine species in WoRMS and BOLD. Due to the large difference among different phylum, all data are presented as logarithm of 10. Every unit in Figure 2 represents the difference of 10 times. Marine Acc.species represents the number of accepted marine species within the specific rank in WoRMS; BOLD species represents the number of species in BOLD; Barcoded represents the number of barcoded species in BOLD.