Relationship Alalysis Of The Performance And Polymorphism Of Bola In Chinese Cattle

Four cattle breeds, including Qinchuan, Luxi, Nanyang, Jinnan, were used as experimental population, which were studied using PCR-RFLP and SSCP. Genetic variation in the exon 2 of DRB3 and exon 2 of DRA of bovine MHC were studied in all four breeds. The association between genetic markers and performance traits were analyzed by using least square analysis of general linear model (GLM) , the results were as follows:The dominance genotype and allele were diffirent from exon 2 of DRB3 in diffirent breed. To HaeⅢ-RFLP loci,Genotype AB and BC were dominant of all breeds ,allele B and C were dominant in Qinchuan, Luxi, Nanyang, but allele A were dominant in.To MspⅠ-RFLP loci, genotype AB were dominant in Qinchuan, Nanyang and Jinnan,but genotyoe BB were dominant in Luxi.Allele A and B were similar, but allele B was higher than allele A. It is not polymorphism in TaqI -RFLP loci. Statistical results showed that polymorphic sites for HaeIII of Nanyang DRB3 locus and polymorphic sites for MspI of Luxi DRB3 locus have not fitted with Hardy-Weinberg Equilibrim.The genotype AF and allele A were dominant in polymorphic sites for SSCP of Qinchan and Jinnan DRA locus. The genotype BC were dominant in Luxi and BF in Nanyang. Allele B were dominant in Luxi and Nanyang. Statistical results showed that polymorphic sites for SSCP of Qinchuan, Jinnan and Nanyang DRA locus have not fitted with Hardy-Weinberg Equilibrim.The polymorphism information content (PIC) values were high polymorphic (PIC>0.50) in polymorphic sites for HaeIII of four breeds DRB3 locus and for SSCP of four breeds DRA locus and were moderate polymorphic for MspI of four breeds DRB3 locus, which means two gene loci have high polymorphism and large variation.Sequence for DRB3 gene exon 2 demostrated that there were a lot of mutations at position 18,19,24,26,64,65,75,76,96,97,127,135,146,154,155,157,165,167,188,196,199,207,208,209,217,219,220,241,242,245,246. By digesting the PCR product with HaeIII and MspI, there were four polymorphic sites at position 154,155,157,165,167. Sequence for DRA gene exon 2 demostrated that there were two mutations at 116 and 197, i.e. G→A and T→C, respectively.During the research of association between genetic markers and performance traits , the age showed a highly significant positive effect on some performance,but not the genetic maker. The genetic maker of HaeⅢ-RFLP for 18 months Nanyang DRB3 gene exon 2 locus had a significant effected on body length. The genetic maker of SSCP for 2 years Nanyang DRA gene exon 2 locus had a significant effected on height at withers. The genetic maker of SSCP for 3 years Nanyang DRA and DRB3 gene exon 2 locus had a significant effected on all performance. And genotype AC had a significant effected on body measures,but others genotype hadn't.