Mutations Of Genes And Their Effects On Production Traits And Establish A Detection Method Of Recessive Hereditary Disease-causing Gene Mutation

The study contained two parts. In the first part, a total of 483 Holstein cows were used as the research object. Five candidate genes from our previous SNP chip screening (PTHRP、TGFB1、PTK2、MAF1 and PHF20) were screened mutation sites and detected, and then the SNPs were analyzed the association between polymorphism with milk traits and reproduction performance. And it will provide a scientific basis to find the effective molecular genetic markers. In the second part study, the four molecular screening methods of four diseases causative gene mutation points (SMA, BHZD, Hemophilia A and Degenerative Axonopathy) were established:PCR-RFLP method. And we used gene sequencing to validate the PCR-RFLP. And the PCR-RFLP was applied in a total of 128 Holstein cows to find harmful allelic gene. The main results are as follows:1, The PTHRP gene mutation have a significant impact on milk performance, indicating that the gene exon is highly conserved sequence. We found a C/T mutation in PTHRP intron 1 gene, then the SNP was analysed the association with milk traits, the results showed that it had significant effect (P<0.05) with the milk yield of 305, the total milk yield and the total protein yield in the second lactation, and CC genotype was higher than the other genotypes; And the SNP was analysed the association with reproductive traits, the results showed that it had significant effect (P<0.05) with the birth weight in the first lactation and the third lactation, and CC genotype was weighter than the other genotypes. And we did not found mutations in the PTHRP gene exonl, exon2, exon3 and exon4.2, The G/A mutation of the PTK2 intron5 was was analysed the association with reproduction and milk traits. And the birth weight in the second lactation of GA genotype was significantly weighter than the GG genotype(.P<0.05), the trend of GA> AA> GG And it had not a significant effect with the milk production traits in dairy cattle, but the milk yield and the total protein yield in the first lactation of GG genotype were greater than the AA genotype.3, There is a significant difference, MAF1 gene exon4 A/G mutation on total protein content, calving interval, days open. The total protein yield in the second lactation of AA genotype was significantly higher than the GG genotype(P<0.05); The birth weight in the second lactation of GG genotype was significantly weighter than the AG, AA genotype(P<0.05); The calving interval and the days to conception after calving in the third lactation of AG genotype was significantly longer than GG, AA genotype(P<0.05).4, There is a significant difference, PHF20 gene intron10 A/G mutation on milk yield, the total protein yield, the birth weight, calving interval. The milk yield of 305 and the total milk yield in the first lactation of AG genotype was significantly higher than AA genotype(P<0.05), the trend of GA> GG> AA. The total protein yield in the first lactation of AA genotype was significantly higher than GG genotype(P<0.05), the trend of AA> AG> GG. The weight birth in the first lactation of AA genotype was significantly weighter than AG and GG genotype(P<0.05). The weight birth in the second lactation of AG genotype was significantly weighter than A A and GG genotype(P<0.05), the trend of AG> AA> GG. The calving interval in the third lactation of AA genotype was significantly longer than AG and GG genotype(P<0.05), the trend of AA> AG> GG.5, We only found two mutations on TGFB1. One was G/A mutation in the exon2 that was same to the report of NCBI(rs111025888). And the other was T/C mutation in the intron5 that was not reported previously. And the exon1, exon2, exon3 exon4 and exon5 in the sequence is more conservative, lower mutation frequency.6, The technique of PCR-RFLP was established to detective causative gene mutation of four kinds of recessive genetic disease (BHZD, SMA, Hemophilia A and Degenerative Axonopathy). And we used the sequencing to confirm the accuracy of this technique.7, A total of 128 Holstein cows were detected by the technique that we established, and no individual that carried the disease gene had been found.