Casein Gene Polymorphism of Goat in Thailand

The genetic polymorphism of the casein genes and the evaluation of haplotype variability in Saanen and Thai Native breeds in Thailand were investigated. The 23 Saanen and 42 Thai Native goats were genotyped at CSN1S1, CSN2, CSN1S2, and CSN3 loci using sequencing techniques. Three variants of A, C, and E on the CSN1S1 gene locus were demonstrated. The genotypic frequencies of CSN1S1 AA, AC, and AE are shared by over 80% of the population. The CSN2 A and F alleles were observed. The CSN2 genotypes of AA, AF, and FF were indicated with the majority of AF frequency. The 2 alleles (A and B) were found on the CSN1S2 gene locus. The prevalence of the CSN1S2 A was approximately 80-90% in frequency in populations. Only AA (70%) and AB (30%) genotypes were observed. Seven CSN3 variants (A, B, D, H, F, N1, and N2) were found in populations. More than 95% in frequency were A, B, and D alleles. The novel CSN3 N1 and N2 were first reported here. Ten of the CSN3 genotypes (AA, AB, BB, AD, AH, BD, BF, DD, AN1, and AN2) were manifested. In this study, most point mutations were missense, and one insertion of a short sequence was found at the 19th exon of CSN1S1 allele E. The 27 casein haplotypes were figured. Only 10 haplotypes were discovered in the Saanen breed, whilst 23 haplotypes appeared in the Thai native breed. Interestingly, the presence of both CSN1S2*A (90%) and CSN2*A (70%) was the most frequent haplotype in the Saanen breed (a huge milk product), while the Thai native goat was not remarkable. Further study on the association of the CSN1S2*A-CSN2*A haplotype and milk production traits may suggest.