Single nucleotide polymorphisms (SNPs) within Bov-A2 SINE in the second intron of bovine and buffalo k-casein (CSN3) gene.

The genetic polymorphism of an entire Bov-A2 element located in the second intron of the buffalo and bovine k-casein (CSN3) gene was investigated by amplification and sequencing of PCR products. Single nucleotide polymorphisms were detected. A PCR-RFLP method was developed to detect an A or G mutation at position 605 of bovine Bov-A2 element which creates a BfaI polymorphic site. The frequencies of the B allele, with the BfaI site, were for 0.275, 0.775, 0.750, 0.975, respectively, for Italian Holstein Friesian, Grey Alpine, Friuli Red Pied and Reggio bovine breeds. The mutation rate (substitutions and deletions/insertions per nucleotide site per year) was 2.5 x 10(-9) for Bov-A2 sequences in the second intron of CSN3. The comparison with other Bov-A2 elements suggests that this retroelement might be an important source of single nucleotide polymorphism for analysis of Bovidae genomes.