Unveiling the close relationship between Betta burdigala and Betta uberis through DNA barcoding based on COI Gene

A Wild Betta burdigala is only known from Bangka Island, while a Wild Betta uberis resides in Kalimantan Tengah and Kalimantan Barat in Indonesia. Both species share numerous physical characteristics, particularly in the meristic count, body color, and specific habitat. In this study, we estimate the degree of similarity between Betta burdigala and Betta uberis using DNA barcoding based on the Cytochrome Oxidase Sub Unit I (COI) gene. The COI gene is a unique and small gene which found in mitochondrial DNA and is used in the DNA barcoding approach to identify species. This approach allows for the analysis of species similarities and the learning of the evolutionary histories of those species. Based on the COI gene, Betta burdigala and Betta uberis have a close genetic distance and a DNA similarity of 96.66%, much higher than other bettas. They differ by eight nucleotide bases, and their genetic distance is 0.04, while a genetic distance between 0.010 and 0.099 is considered to be low and indicative of high similarity. According to the phylogenetic tree, these species are descended from a single, closely related ancestor on the same branch. Based on the COI gene, we assume that they are identical. Additionally, we advise conducting additional research using the mitochondrial DNA complex and in-depth morphological examination to confirm the accuracy of the study's findings.