A genome-wide scan for signatures of selection in Azeri and Khuzestani buffalo breeds

Background: Identification of genomic regions that have been targets of selection may shed light on the genetic history of livestock populations and help to identify variation controlling commercially important phenotypes. The Azeri and Kuzestani buffalos are the most common indigenous Iranian breeds which have been subjected to divergent selection and are well adapted to completely different regions. Examining the genetic structure of these populations may identify genomic regions associated with adaptation to the different environments and production goals. Results: A set of 385 water buffalo samples from Azeri (N= 262) and Khuzestani (N= 123) breeds were genotyped using the Axiom((R)) Buffalo Genotyping 90 K Array. The unbiased fixation index method (F-sT) was used to detect signatures of selection. In total, 13 regions with outlier F-ST values (0.1%) were identified. Annotation of these regions using the UMD3.1 Bos taunts Genome Assembly was performed to find putative candidate genes and QTLs within the selected regions. Putative candidate genes identified include FBXO9, NDFIP1, ACTR3, ARHGAP26, SERPINF2, BOLA-DRB3, BOLA-DQB, CLN8, and MYOM2. Conclusions: Candidate genes identified in regions potentially under selection were associated with physiological pathways including milk production, cytoskeleton organization, growth, metabolic function, apoptosis and domestication-related changes include immune and nervous system development. The NIL identified are involved in economically important traits in buffalo related to milk composition, udder structure, somatic cell count, meat quality, and carcass and body weight.