Distribution of αs1-Casein Genotype in Dairy Goat

• Main Authors: Shu-Yu Hsieh, 謝書瑜
• Other Authors: Yan-Ming Horng, Ph. D.
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/58361902209334718698

碩士 === 國立嘉義大學 === 動物科學系研究所 === 99 === The purpose of this study is to investigate the αs1-casein gene polymorphisms in Taiwan dairy goats were analyzed by polymerase chain reaction-restriction enzyme fragment length polymorphism (PCR-RFLP) and allele-specific polymerase chain reaction (AS-PCR). The ethanol and heat stability of goat milk were also detected to investigate the relationship with αs1-casein genotype. Genomic DNA isolated in blood samples from 160 dairy goats was detected for genotypes of αs1-casein gene (CSN1S1) by PCR-RFLP and AS-PCR. Eleven αs1-casein genotypes were found: AA, AE, AF, A01, EE, EF, EN, E01, FF, F01 and N01. The frequencies of these genotypes were 0.13, 0.13, 0.29, 0.02, 0.02, 0.19, 0.01, 0.03, 0.13, 0.04 and 0.01, respectively. The most common genotype was AF (0.29), and the least common was N01 (0.01). In CSN1S1 alleles, the frequency of F allele (0.40) was the highest than others, which showed that CSN1S1 F allele was the most common allele of all examined dairy goats. Since SDS-PAGE revealed that the milk of AF, EF, FF and F01 genotypes had a specific protein fragment at about 23 kDa, the fragment could become a specific protein for selecting CSN1S1 F. Milk collected from 100 milking dairy goats, including 74 does and 25 maiden does, for detection of ethanol and heat stability revealed ethanol concentrations of ranging from 35 to 65% and temperatures of ranging from 90 to 140°C. The average ethanol and heat stability of milks were 47.7±5.1% and 108.2±4.9°C, respectively. Ethanol stability also correlated with heat stability (p<0.05, r=0.29658), , so ethanol stability is in accordance with heat stability of goat milk. The ethanol and heat stability in maiden does were both significantly lower than in does (p<0.001), which showed that parity may affect the ethanol and heat stability of goat milk. However, the associated mechanisms require further study. In αs1-casein genotype, the ethanol and heat stability had no significantly difference between different αs1-casein genotypes (p>0.05), but the ethanol and heat stability of the genotype with F allele (AF, EF and FF genotype) were both higher than others. These comparison results showed that CSN1S1 F could be a selected gene for dairy goat of heat stability.