Polymorphism of molecular-genetic systems in the Polish red cattle

The object of this study was to investigate gene polymorphism in the Polish Red (PR) cattle, a local Polish breed included in the FAO conservation programme. Milk protein genes and other genes with possible effect on production traits were analysed. Frequencies of different gene variants were compared with those in the Polish Friesian cattle. The following gene polymorphisms were analysed with PCR/RFLP technique: milk protein genes--kappa-casein and beta-lactoglobulin, growth hormone (GH), PitI (a transcription factor) and leptin. Moreover, SSCP analysis was performed of myostatin (MSTN) gene at the site previously shown to cause muscle overgrowth in Belgian Blue double-muscled cattle. A significant difference was found in this study between kappa-casein A and B allele frequency in PR and Friesian cattle. No such differences were found in the frequency of A and B alleles of beta-lactoglobulin, L and V alleles of GH, A and B alleles of PitI, and A, B and C alleles of leptin gene. In the analysed group of the Polish Red cattle three animals were found with the rare AI genotype of -lactoglobulin. No such genotype was identified in analysed Friesians. Moreover, 8 PR animals were identified carrying a mutation in MSTN gene, possibly identical to that causing the double-muscled phenotype in some breeds of meat cattle.