The Relationship Of Polymorphisms Of PRNP And BLAD With Sperm Motility In Bulls

Bovine spongiform encephalopathy (BSE) is one kind of the prion diseases,knonwn as transimissible spongiform encephalopathies (TSE), which is characterizedby long incubation and high fatality rate and harmful to animal and human. Accordingto large numbers of studies, the polymorphisms of bovine prion protein gene(PRNP)are associated with the susceptibility and resistance of BSE of individuals, such as23bp in-del and12bp in-del in non-coding regions and24bp in-del in coding regions.The mutation in coding regions will change the kind of amino acid in proteincoden by bovine CD18gene, resulting the reduction or lack of expression of intergrinlocated in the surface of neutrophil leucocytes.Because of that, neutrophil leucocytescan not pass through the endothelial layer and reach to the infection area, causingbovine leukocyte adhesion deficiency (BLAD) which is a lethal autosomal recessivedisease.In order to improve the genetic traits of the bull, the polymorphisms of thebovine CD18gene were tested to select the excellent disease-resistant individuals.In this study, the polymorphisms of bovine PRNP gene and the prion proteinexpression levels were detected and researchde by conventional PCR, non-denaturingpolyacrylamide gel electrophoresis, clone sequencing and Q-PCR. Thepolymorphisms and the genotype distribution of the PRNP gene in the bull werestatistics and the sperm motility and the expression level of prion protein of diferentgenotype bull were analyzed. Using the same method, a disease-related singlenucleotide polymorphisms (SNP) site in the bull was tested for gettingdisease-resistant individuals. The individuals which have excellent reproductivecapacity and disease resistance can be screened by the study results.In the present study and analysis,23bp in-del,12bp in-del and24bp in-delwere detected in the non-coding regions and coding regions of bovine PRNP which issame to the previous report. Results showed that polymorphisms at the23bp and12bp obtained three genotypes such as in-in, in-del and del-del. While thepolymorphisms at24bp fragment obtained two genotypes such as in-in and in-del.The dominant genotypes at12bp and23bp in-del fragment length polymorphisms were heterozygous and the frequencies was69.12%and77.94%, respectively.Furthermore, the dominant genotype at24bp in-del polymorphisms was in-inhomozygote （92.65%）. Comparison analysis indicated that the volume of oneejaculation with12bp in-del and del-del genotype population was significantly higherthan that of12bp in-in genotype （P<0.05）, the fresh semen motility with23bp in-ingenotype population was significantly higher than that of23bp in-del genotype, thenumber of straw freezing sperm once ejaculation and the number of straw per yearwith23bp del-del genotype population was significantly higher than that of23bpin-in genotype （P<0.05）, and the number of straw per year with24bp in-ingenotype population was significantly higher than that of24bp in-del genotype（P<0.05）. No significantly difference was found between other physiologicalperformances. It proposed that there had a negative relationship between theresistance and production performance for Holstein bull and the results in the studycould be used as molecular marker for bull selection. Because of small proportion,efforts should be increased for increasing the excellent characteristics of individualsin the population. The relation of single nucleotide polymorphisms (SNPs)(Aâ†'Gmutation) in bovine BLAD gene and semen quality traits were studied, the correlationanalysis was carried out further. Only two genotypes, mutations in dominanthomozygotes AA and dominant miscellaneous closing Aa were detected in thesample,whose frequencies were95.72%and4.28%respectively, recessivehomozygous aa was undetected. Sperm motility differences among the differentgenetic groups were not significant.