Genome-Wide Survey of signature of positive selection in Khuzestani and Mazandrani buffalo breeds

Identification of selection targeted genomic regions is one of the most challenging areas of research in animal genetics, particularly in livestock. We carried out a genome-wide scan for signatures of positive selection to identify genomic regions that had been under selection in Iranian Khuzestani and Mazandrani buffalo breeds. A total of 148 water buffalo from Khuzestani (N=121) and Mazandrani (N=27) buffalo breeds were genotyped using Axiom® Buffalo Genotyping 90K Array. Unbiased method of population differentiation index (FST) was applied to detect signatures of selection. In total, 23 regions exceeding the 0.1 percent threshold of the empirical posterior distribution were identified as extremely differentiated. These selected genomic regions were surveyed to find encoding putative candidate genes and 64 genes and 27 QTL were extracted from the corresponding areas in UMD3.1 Bos Taurus Genome Assembly. Some of these genes have previously reported as signature of positive selection in the last studies. Some of these genes were also found to be involved in milk production traits and domestication-related changes include sensory perceptions, brain and neural system development, pigmentation, and geographic adaptation. Also, survey on extracted QTLs was shown that these QTLs involved in some economicl important traits in buffalo such as feed conversion ratio, subcutaneous fat, body weight, average daily gain, type, Meat tenderness, milk production conentent, udder attachment, calf size and calving ease traits. However, it will be necessary to carry out more association and functional studies to demonstrate the implication of these genes.