The Relation Analysis Of Milk Character And Polymorphism Of CSN1S2 Gene In China Holstein And Huanggainai Cattle

The CSN1S2 gene was studied using PCR-SSCP in China Holstein and Huanggainai cattle and analyzed the genetic variation. The relationship between genetics markers and the milk character were analyzed. The aim is to explore perfect markers in twinning which can provide theory base on breeding in cattle. The results were follows:1. The analysis on polymorphism and sequence on the 5'flank of CSN1S2 geneSix genotypes AA, BB, CC, AB, AC and BC were found in PCR amplification region of the premier CSN1S2P1 in China Holstein and Huanggainai cattle. The polymorphism information content (PIC) values were moderate polymorphism (0.5>P>0.25), which means large variation in the loci. Sequence for the region demonstrated that there were lots of mutations. There was one mutation with 2370bp (G→A) in the AA genotype. The positions of 2187bp (T→G), 2423bp (T→C), 2505bp (C→A), 2532bp (C→T) and 533bp (T→G) in the BB genotype were mutation. The positions of 2370bp (G→A), 2405bp (C→A) and 2525bp (added G) in the CC genotype were mutation.2. The analysis on polymorphism and sequence on the exon2 of CSN1S2 geneThree genotypes AA, BB and AB were found in PCR amplification region of the premier CSN1S2P2 in China Holstein and Huanggainai cattle. At the position 4129bp (T→G) was a same mutation in the AA and BB genotype. There were two mutations with the position 4263bp (added G) and 4346bp (T→C) in the BB genotype. There were two mutational sites in BB genotype with 4263bp and 4346bp which were synonymous mutation.3. The analysis on polymorphism and sequence on the exon4 and exon5 of CSN1S2 geneThree genotypes AA, BB and AB were found in PCR amplification region of the premier CSN1S2P3 in China Holstein, two genotypes AA and AB were found in Huanggainai cattle. There were three mutations with the position 6892bp (T→C), 6920bp (A→G) and 7174bp (added C) in the AA genotype. The position of 6920bp (A→G) in the BB genotype was mutation. 4. The analysis on polymorphism on the exon3 of CSN1S2 geneTwo genotypes AA and BB were found in PCR amplification region of the premier CSN1S2P4 in China Holstein, but only one genotype AA in Huanggainai cattle.5. The relation of the polymorphism and milk characterWe studied the CSN1S2 gene as candidate gene about milk yield character of China Holstein and Huanggainai cattle. The study showed that the milk yield of China Holstein with genotype BC was the highest in CSN1S2P1 amplifyed fragment. The protein ratio of China Holstein with genotype AA was the highest in CSN1S2P2 amplifyed fragment and it was suit to be MAS(Marker Assistant Select)of China Holstein. The fat percentage and protein ratio of Huanggainai cattle with genotype AA was significantly higher than those with genotype BB and AB in CSN1S2P2 amplifyed fragment, and the milk yield also higher than other two genotypes. So it was suit to be MAS of Huanggainai cattle.