Sequencing and annotation of the endangered wild buffalo (Bubalus arnee) mitogenome for taxonomic assessment

The wild water buffalo ( Bubalus arnee ) is one of the most endangered and least studied large bovid in the Indian subcontinent. India retains 90% of the estimated global population of >4000 individuals as two fragmented populations in Assam and Chhattisgarh, both threatened by habitat loss and degradation, hunting, disease from livestock, and hybridization with the domestic buffalos. Small, fragmented population size and potential hybridisation pressures from co-occurring domestic buffalos are the major conservation challenges. For the first time, we sequenced the 16,357 bp long mitogenome of three opportunistically collected wild water buffalo samples from Assam (n = 1) and Chhattishgarh (n = 2). The annotated sequence has a base composition of 26.4% T, 26.6% C, 33.1% A and 13.9% G depicting an AT-rich mitogenome composition, including 13 protein-coding genes (11,361 bp), 22 transfer RNA (tRNA) (1514 bp), two ribosomal genes (2525 bp), and a non-coding control region (928 bp). The gene order is conserved with other bovid species. Comparative mitogenome analyses showed both populations are genetically similar but significantly different from domestic buffalo. We also identified structural differences in seven tRNA secondary structures between both species. The genetic distance between wild buffalo and other bovids varied between 0.103 and 0.122. Multiple Bayesian phylogenetic trees showed that both wild and domestic water buffalo formed sister clades which were paraphyletic to other potentially sympatric species of genus Bos. This study provides baseline information on wild buffalo mitogenome for further research on phylogeny, phylogeography and hybrid assessment and help conserving this endangered species.