Overcoming taxonomic challenges in DNA barcoding for improvement of identification and preservation of clariid catfish species

Abstract

DNA barcoding without assessing reliability and validity causes taxonomic errors of species identification, which is responsible for disruptions of their conservation and aquaculture industry. Although DNA barcoding facilitates molecular identification and phylogenetic analysis of species, its availability in clariid catfish lineage remains uncertain. In this study, DNA barcoding was developed and validated for clariid catfish. 2,970 barcode sequences from mitochondrial cytochrome c oxidase I (COI) and cytochrome b (Cytb) genes and D-loop sequences were analyzed for 37 clariid catfish species. The highest intraspecific nearest neighbor distances were 85.47%, 98.03%, and 89.10% for COI, Cytb, and D-loop sequences, respectively. This suggests that the Cytb gene is the most appropriate for identifying clariid catfish and can serve as a standard region for DNA barcoding. A positive barcoding gap between interspecific and intraspecific sequence divergence was observed in the Cytb dataset but not in the COI and D-loop datasets. Intraspecific variation was typically less than 4.4%, whereas interspecific variation was generally more than 66.9%. However, a species complex was detected in walking catfish and significant intraspecific sequence divergence was observed in North African catfish. These findings suggest the need to focus on developing a DNA barcoding system for classifying clariid catfish properly and to validate its efficacy for a wider range of clariid catfish. With an enriched database of multiple sequences from a target species and its genus, species identification can be more accurate and biodiversity assessment of the species can be facilitated.

Questioning inbreeding: Could outbreeding affect productivity in the North African catfish in Thailand?

“…This suggests that the SBR-KSN and NYK populations were derived from distinct lineages. Chalermwong et al [ 73 ] asserted that a species complex was identified within the North African catfish, which was characterized by substantial intraspecific sequence divergence, although it was classified under the same species using a species delimitation approach based on DNA barcodes. Moreover, ZZ/ZW sex determination system, which is likely the ancestral system for the North African catfish, is the same as the systems reported in Africa and Israel.…”