Correlation Between SPEF2 Gene Variation And The Litter Size Of Pig Breeds

The sperm flagella 2(SPEF2)gene is crucial for the sperm development and function of tail cilium,together with the male animal fecundity.Gene SPEF2 highly expressed in the sperm cilium,spermatocyte and round spermatid.It is reported that mutation in SPEF2 gene will lead to malformation with shortened tail and the loss of motive ability of sperm in Yorkshire pig.SPEF2 gene is thought to control both of spermatogenesis and sperm motility.To further investigate the relationship between the SPEF2 gene mutation and fecundity of pig breed,we used PCR product direct sequencing and AS-PCR technology to detect the L1 element insertion and single nucleotide polymorphism(SNP)in the intron 30 of SPEF2 gene of Nuogu,Xiang pig,and Large White pigs.The correlation between the SPEF2 gene mutation and litter size of Xiang pig was further explored.The main results were as following:1.Although L1 element was not detected from the intron 30 of SPEF2 of samples,but two SNP sites were screened out with allele polymorphism of 19642 G>A and 19886 G > T,respectively.2.Based on those finding,three molecular marker detection technologies for insertion of L1 element,and genotypes of sites 19642 G> A and 19886 G> T were established with the minimum amount of the target genomic DNA of 0.518 ng and the repeatability of 100%.3.Using the three established technologies,the three varieties were detected in three populations of Nuogu(n=94),Xiang(n=278),and Large White(n=185)pigs.The L1 element were not presented in genome of all three pig breeds.The first site,19642 G> A,existed to be AA and AG genotypes with dominant types of AG genotype in three pig populations.There was no correlation between the frequency of 19642 G> A and the litter size of Xiang pig.For the second site,19886 G > T,only two genotypes of GG and GT were determined without TT type,and the GT type was mainly existed in three pig breeds.Furthermore,the distribution of 19886 C >G was significantly associated with the litter size of Xiang pig.The litter size with GT genotype gave much more litter size than that with TT types at site 19886 G > T.And the 199886 G> T substitution might change the binding site of the splicing factor binding protein SRSF1 to its target sequence based on bioinformatics analysis.It suggested that the second SNP site,199886 G> T,might affect the intron splicing of SPEF2 to regulate of litter size of Xiang pig.In this study,the relationship between SPEF2 gene mutation and litter size of Xiang pig were verified,and the established molecular marker detection technologies could be used for breeding practice in Xiang pig.