Association of ss-casein gene polymorphism with milk production traits in buffalo (Bubalus bubalis)

Milk proteins consist of casein and whey proteins. The investigation was carried out to detect the polymorphism in beta-casein gene at the DNA level and study its association with milk production and constituent traits. Lactating animals (200) belonging to Muffah, Bhadawari, Surd and Mehsana breeds were included. Genomic DNA was isolated from blood samples and used to amplify 465 bp fragment of beta-casein gene (partial exon 7) by PCR. PCR- SSCP technique was used to study the variability in this fragment. The fragment was polymorphic. In 465 bp fragment, 4 genotypes, viz. AA, AB, AC and BB were identified in different breeds. The genotypic frequencies of AA, AB, AC and BB genotypes were 0.36, 0.56, 0.04 and 0.04, respectively, in Mehsana breed. In Murrah, the frequency of AA, AB and AC genotypes was 0. 10, 0.80 and 0. 10, respectively. Bhadawari breed had AA and AC genotypes with genotypic frequencies as 0.96 and 0.04, respectively, while in Surti, AA and AB genotypes had 0.68 and 0.32 as their genotypic frequencies, respectively. The least square analysis for the association study of 465 bp fragment showed significant effect of AB genotype on total SNF yield only in Surti buffaloes. The information generated by this study can be utilized for identification of animals with superior alleles.