Identification of selective signatures associated with resistance to bovine leukosis ‎‎(BLV) in Iranian Holstein cows

Bovine viral leukemia (BLV) is one of the deadliest viral diseases that is associated with many economic losses in the dairy industry, such as reduced production capacity and reproductive performance of infected animals and their eventual culling. The aim of this study was to identify the selection signatures associated with resistance to BLV in Iranian Holstein cows. For this purpose, a total of 152 animals were genotyped for 30,105 SNP markers using GGP Bovine LD v4 chips. After quality control of the initial data, 23,513 SNP markers in 140 animals of cattle were finally entered for further analysis. The animals used were classified into two groups consisting resistant to disease or healthy (68 animals) and sick (77 animals) animals, and then the regions of the genome that were divergently selected in these animals were evaluated using the unbiased Theta method. The results of this study showed that four genomic regions on chromosomes 1, 13, 20 and 22 were divergently selected in these groups. Study of the genes reported in these regions revealed that some genes such as the STGA1 on chromosome 1, the STK35, EBF4, and PDYN on chromosome 13 and the SLC38A3, RASSF1, and RBM6 on chromosome 22 were previously reported within or adjacent to these genomic regions. Study the function of these genes showed that the genes are involved in the immune system, the regulation of mitotic and meiotic cycles and cancer suppression. Overall, the results of this study can provide a valuable source of information to identify candidate genomic regions or causal genes associated with this disease.