Rohallah Alinaghizadeh, Mohammadreza Mohammad Abadi, Shahin Moradnasab Badrabadi
Department of Animal Genetics and Biotechnology, Shahid Bahonar University of Kerman, Iran.
Pak J Biol Sci. 2007 Dec 1;10(23):4291-4. doi: 10.3923/pjbs.2007.4291.4294.
In cattle, caseins are subdivided into four main groups: alphaS1-, alphaaS2-, beta- and kappa-caseins. kappa-caseins (CSN2) considerably differ from other caseins in structure and other properties. Testing the A and B alleles is of practical importance, because the milk of cows that carry the B allele of CSN3 has a better thermal resistance and shorter coagulation time, better curdles and contains micelles of different sizes. Iranian Sistani cattle (Bos indicus) are a heavy built breed and used as dual-purpose cattle breed in Eastern Iran. This breed is a genetic resource that shows special features of adaptation to rustic environments. One of the most distinctive features of Sistani cattle is its great capability to resist diseases which makes it a potential reservoir of germplasm useful for future crosses. Our main goal was to study DNA-polymorphism of the CSN3 gene in the Iranian Sistani native cattle (Bos indicus) and analyze the information value of CSN3 gene polymorphism as a genetic marker. We genotyped and analyzed 65 animals of this breed using PCR-RFLP. The frequencies of A and B alleles were 0.6385 and 0.3615 and those of AA, AB and BB genotypes were 0.4000, 0.4769 and 0.1231, respectively. In the Sistani Zebu breed, frequency of B allele is higher than other Zebu breeds, indicating that intensive selection for dairy production have been done and indirectly influenced CSN3 allele frequencies.
在牛中，酪蛋白可细分为四个主要类别：αS1 -、αS2 -、β - 和κ - 酪蛋白。κ - 酪蛋白（CSN2）在结构和其他特性上与其他酪蛋白有很大差异。检测A和B等位基因具有实际重要性，因为携带CSN3基因B等位基因的奶牛所产的牛奶具有更好的耐热性和更短的凝固时间，凝乳效果更好且含有不同大小的胶粒。伊朗锡斯坦牛（瘤牛）体型庞大，在伊朗东部用作两用牛品种。该品种是一种遗传资源，展现出适应乡村环境的特殊特征。锡斯坦牛最显著的特征之一是其强大的抗病能力，这使其成为未来杂交中有用的潜在种质库。我们的主要目标是研究伊朗本土锡斯坦牛（瘤牛）中CSN3基因的DNA多态性，并分析CSN3基因多态性作为遗传标记的信息价值。我们使用PCR - RFLP对该品种的65头动物进行了基因分型和分析。A和B等位基因的频率分别为0.6385和0.3615，AA、AB和BB基因型的频率分别为0.4000、0.4769和0.1231。在锡斯坦瘤牛品种中，B等位基因的频率高于其他瘤牛品种，这表明已经针对奶牛生产进行了高强度选择，并间接影响了CSN3等位基因频率。
