1Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, Institute of Cellular and Molecular Biology, School of Life Sciences, Xuzhou Normal University, Xuzhou, 221116, China.
2College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, 712100, China.
3 Corresponding author E-mail:chenhong1212@263.net, Tel: +86-29-87092004, Fax: +86-29-87092164.
* These authors contributed equally to this work.
Genetic polymorphisms of prolactin (PRL) and prolactin receptor (PRLR) genes in Chinese Holstein cattle were detected by PCR-SSCP methods. Polymorphisms were observed in both genes and direct sequencing confirmed the A>G mutation at position 8398 in exon 4 of PRL gene and the A>C mutation at position 7866 in intron 9 of PRLR gene. The frequencies of allele A/B and C/D were 0.894/0.106 and 0.781/0.219 for PRL and PRLR genes, respectively. Chinese Holstein cows with genotype BB were observed to be higher milk yielders than genotypes AA and AB (P<0.05). It is concluded that the polymorphism in the PRL gene may be a genetic marker in breeding for milk yields in Holsteins, but further validation is required.
Cattle, milk yield, prolactin gene, prolactin receptor gene, polymorphism
