Maternal genetic diversity and phylogenetic analysis of Indian riverine and swamp buffaloes: insights from complete mitochondrial genomes.

ABSTRACT

This study explored the genetic diversity and evolutionary history of riverine and swamp buffaloes in India, utilizing complete mitochondrial genome sequences. Through comprehensive sampling across varied agro-climatic zones, including 91 riverine buffaloes from 12 breeds and 6 non-descript populations, along with 16 swamp buffaloes of the Luit breed, this study employed next-generation sequencing techniques to map the mitogenomic landscape of these subspecies. Sequence alignments were performed with the buffalo mitochondrial reference genome to identify mitochondrial DNA (mtDNA) variations and distinct maternal haplogroups among Indian buffaloes. The results uncovered the existence of 212 variable sites in riverine buffaloes, yielding 67 haplotypes with high haplotype diversity (0.991), and in swamp buffaloes, 194 variable sites resulting in 12 haplotypes, displaying haplotype diversity of 0.950. Phylogenetic analyses elucidated the genetic relationships between Indian buffaloes and the recognized global haplogroups, categorizing Indian swamp buffaloes predominantly into the SA haplogroup. Intriguingly, the haplogroup SB2b was observed for the first time in swamp buffaloes. Conversely, riverine buffaloes conformed to established sub-haplogroups RB1, RB2, and RB3, underscoring the notion of Northwestern India as a pivotal domestication site for riverine buffaloes. The study supports the hypothesis of independent domestication events for riverine and swamp buffaloes, highlighting the critical role of genetic analysis in unraveling the complex evolutionary pathways of domestic animals. This investigation contributes to the global understanding of buffalo mitogenome diversity, offering insights into this important livestock species' domestication and dispersal patterns.