Phylogenetic Analysis of Crayfish Species Using Mitochondrial DNA Markers

Abstract

Phylogenetic analysis of crayfish species was executed using sequences from three mitochondrial gene regions: 16S rRNA, cytochrome oxidase I (COI), and cytochrome b (Cyt b). This analysis is crucial for molecular taxonomic identification and biodiversity assessment because it determines the level of variation in gene regions. However, information data on potentially mitochondrial gene regions are lacking for phylogenetic studies in commercial crayfish species. The three regions of mitochondrial genes were used in this study to determine phylogenetic relationships between crayfish species. The phylogenetic trees were constructed to better understand the evolutionary relationship between crayfish species. The neighbour-joining (NJ) and maximum parsimony (MP) methods were used to evaluate the 16S rRNA, Cyt b, and COI genes, which act as molecular markers for the genus Cherax and are used to infer phylogenetic relationships. The composition of nucleotides and their properties were compared among three regions of mitochondrial genes. Phylogenetic analyses between Cherax species revealed that 16S rRNA was the least variable, with a range of 3.8-17.38%, and COI was the most variable, with a range of 4.9-25.74%. All Cherax species are consistently grouped together using three regions of mitochondrial genes. The COI gene sequences were more conserved than the Cyt b and 16S rRNA gene sequences. All of the gene sequences provided sufficient phylogenetic information to distinguish between crayfish species, and thus could be useful molecular markers for species identification.