Polymorphism Analysis Of ABCG2 Gene CDS Domain In Chinese Holstein

This research studied the relationship between polymorphism of CDS in ABCG2 gene and milk production traits by PCR-SSCP and PCR-RFLP in Chinese Holstein. Statistical analysis between polymorphism and milk production traits uses the SAS9.0 ANOVA, and then analysis the structure and characteristic change of ABCG2 protein by bioinformatics. The results were as follow:1. We found a single nucleotide polymorphism (SNP)-A/G-in exon9 was capable of Tyrosine-367 to Cysteine and another SNP-(G/A)-in exon14 was capable of Arginine-578 to Glutarnine (R578Q) in the ABCG2 gene.2. For the exon9 of ABCG2 gene in Chinese Holstein, there were two alleles A and B, and three genotypes AA, AB and BB of the ABCG2 gene exon9. The frequencies of A and B were 0.86 and 0.14; the frequencies of AA, AB and BB were 0.73, 0.26 and 0.01. The PIC (Polymorphism Information Content) was 0.22, indicating that the exon9 of ABCG2 gene had low polymorphism. The difference is no distinct between three genotypes in five milk production.3. For the exon14 of ABCG2 gene in Chinese Holstein, there were two alleles: A and B, and their allele frequencies were 0.93 and 0.07 respectively. Three genotypes (AA, AB and BB) were found in our materials. The frequency of AA is 0.87, AB is 0.12 and BB is 0.01. The PIC (Polymorphism Information Content) was 0.119. The milk production performance, milk yield and milk protein yield of AB individuals were all higher than AA individuals significantly (P<0.05).4. Result of bioinformatics analysis: The secondary structure of ABCG2 protein including alpha-helix 49.69%, the rest 39.67% and extended strand 10.64%; the motif of ABCG2 protein at the domain of 39-288 (score=17.434), including six transmembrane helices and three signal peptide sequence, the cleavage sites between 651 and 652, and the cleavage sequence is LKL-LF. ABCG2 protein is non-secretion protein of located in plasma membrane, the GRAVY is 0.181. On the other hand, we found that the Component and character of ABCG2 protein have changed because of the two SNPs. Secondary structure increased a coil, a helix and a turn, and the same time decreased four sheets by bioinformatics analysis.From the results we can see that: it has affected that ABCG2 gene CDS to the milk production traits of Chinese Holstein, two SNPs of we found in this research can using of MAS. We found that the AGCG2 protein characteristic and second structure changed by arise of two SNPs.