Comparative analysis of Ayrshire and Black Pied cattle breeds by histocompatibility markers.

摘要

The distribution of BoLA-A antigens and BoLA-DRB3 alleles was studied in 127 Ayrshire and 129 Black Pied cattle by means of the microlymphocytotoxicity test (BoLA-A) and PCR-RFLP (BoLA-DRB3) using the restriction endonucleases RSAI, HaeIII and XhoII. The breeds differed significantly in their frequency profiles for the class I antigens W2, W6, W10, W31, W44, W15 and W19. The breeds also differed in the spectrum of BoLA-DRB3 alleles and their frequency distribution. In the Ayrshires, 5 of 18 detected alleles (DRB3.27, DRB3.8, DRB3.10, DRB3.24 and DRB3.28) accounted for 77% of the alleles present. Allele DRB3.2.7 (37.6%), which is classed as a rare allele in Black Pied cattle, was the most common in the Ayrshires. The heterozygosity level observed in the combined sample of Black Pied cattle (0.836) was higher than that in the Ayrshires (0.070). In both breeds, the heterozygosity level was studied in healthy animals and in animals with persistent lymphocytosis (caused by bovine leukaemia virus) andin a group of Ayrshires carrying this virus. Affected animals had a lower level of heterozygosity than healthy animals. The observed heterozygosity level exceeded the expected level in carriers. It is suggested that, in order to increase the resistance of herds to leukaemia, it is important to control the levels of heterozygosity and genetic diversity with respect to BoLA-DRB3.