The objectives of this study were to identify polymorphisms in exon III of the a-lactalbumin gene among three Egyptian goat breeds (Zaraibi, Damascus and Barki) and to investigate the effect of a-lactalbumin gene polymorphism, goat breed, type of birth, season of kidding, litter size and lactation stage on body weight and milk yield traits in Egyptian goats. One hundred and sixty blood samples were collected for DNA extraction; 74 from Zaraibi, 41 from Damascus, and 45 from Barki breeds. Two genotypes, TT and TC, in the a-lactalbumin gene were identified using single strand conformation polymorphism. DNA sequencing resulted in one non-synonymous MT163744: g.128T>C SNP (TCG Ser> CCG Pro) at the sixth nucleotide of a-lactalbumin gene exon III. Barki breed showed the highest heterozygosity (0.260) and effective number of alleles (1.345). The T>C SNP showed non-significant association with body weight traits. Body weights at birth, 3 months and 12 months in Damascus goat were significant and higher than those in Zaraibi. Kids born single were heavier than twins and triplets at birth age. The highest milk yield was recorded for Zaraibi does with three kids and at the first month of lactation stage. Moreover, the T>C SNP in the Zaraibi a-lactalbumin gene may be a useful marker for assisted selection programs to improve goat milk yield trait. |
