Non-homologous COI barcode regions: a serious concern in decapod molecular taxonomy

Biodiversity is well defined with the assistance of taxonomy, the science which classifies organisms with "species" as the basic unit. Presently, in taxonomy, morphological type specimen is complimented with its molecular data from "type" gene sequences and species status is granted. For this, DNA barcoding using standardized DNA gene(s) is performed in which Cytochrome c oxidase I gene of mitochondrial DNA is referred as the primary barcode region for animal kingdom. Being a popular mitochondrial marker, this gene is reported to possess two barcode regions with limited overlap, "Folmer" and "Palumbi" regions particularly in decapod crustaceans. Here we demonstrate the issues originated as a result of incorporation of both these barcode regions together in addressing various aspects of DNA barcoding like specimen identification, population analysis, and phylogeny in decapod crustaceans using COI sequences ("Folmer" and "Palumbi") of Macrobrachium rosenbergii as reference sequences.