SINE elements are frequently studied in the context of their location, evolution and hypothetical functions. In the present paper, the T→C transition at nucleotide position 1564 located within the Bov-A2 SINE element in the promoter region of the CYP21 gene was investigated in seven cattle breeds including Polish Holstein-Friesian, Jersey, Montbeliard, Charolais, Angus, Hereford and Limousin. The frequency of homozygotes (AA) and heterozygotes (AB) was similar for the Polish Holstein-Friesian breed, whereas a complete monomorphism was found in Jersey cattle. Moreover, only two genotypes (AA and AB) were observed in Limousins. For the remaining breeds, the frequency of homozygotes (AA) was the highest ranging from 0.680 for Charolais to 0.865 for Montbeliard.

Key words: Beef cattle, Bov-A2 element, CYP21 gene, Dairy cattle