EN
The bovine kappa-casein (CASK) gene is known as a potential quantitative trait locus in dairy cattle breeding. However, the molecular basis of the effect of the CASK allele B on different milk properties remains unclear. In this report, a 214 bp fragment of the 5' untranslated region of the CASK gene containing 5 potential consensus sequenses for different transcription factors was PCR-amplified to find RFLPs. A Dde I RFLP was identified. In a population of 112 Bos taurus (86 cows and 26 bulls of Polish Black and White crossbred Holstein-Friesian) and 7 Bison bonasus individuals, 7 had no recognition sites for Dde I, 23 were heterozygous and 89 were cut completely into two fragments.