Study On Candidate Genes Related To High Prolificacy In Small Tail Han Sheep

To detect the polymorphisms of GDF9, VEGF and PROP1gene in precociouspuberty and high prolificacy breeds (Hu sheep and Small Tail Han sheep) and latematurity and low prolificacy breeds (White Suffolk, China Merino sheep and Texel),PCR-RFLP, and sequence analysis were used. The relation between the polymorphismsand high prolificacy in sheep was also studied to provide a scientific basis formarker-assisted selection for prolificacy in sheep The results were as follows.1. The results indicated that the FecTT mutation of GDF9gene was not detected ineleven sheep breeds tested.2. The results of VEGF gene were as follows. Only the products amplified by primersB5displayed polymorphisms. The product of primer B5was digested with restrictionendonucleases Avaâ… ,Pstâ… and BsaHâ… , respectively. Polymorphic Avaâ…  site wasdetected at14752Câ†'T mutation in intron5of VEGF gene. Three genotypes CC, CT andTT were found in Small Tail and Hu sheep, two genotypes CC and CT were found inWhite Suffolk and Chinese Merino sheep. The ewes with genotype TT had0.70(P<0.05)or1.05(P<0.05) lambs more than those with genotype CT or CC, the ewes with genotypeCT had0.35(P<0.05) lambs more than CC genotype. Polymorphic Pstâ…  site wasdetected at the14758Gâ†'T mutation in intron5of VEGF gene. Two genotypes GG and GTwere found in Small Tail Han, Hu and Chinese Merino sheep, only GG genotype wasfound in White Suffolk. The difference of least squares mean for litter size of GG and GTwas not significant (P>0.05) in Small Tail Han sheep. Polymorphic BsaHâ…  site wasdetected at the14908Câ†'T mutation in exon6of VEGF gene. Three genotypes CC, CTand TT were found in Small Tail, Hu and Chinese Merino sheep, two genotypes CT andTT were detected in White Suffolk. The difference of least squares mean for litter size ofCC, CT and TT was not significant （P>0.05）in Small Tail Han sheep.3. The results of VEGF gene were as follows. Only the products amplified by primerC5displayed Hhaâ… -RFLP polymorphisms. Three genotypes (CC, CT and TT) weredetected in Small Tail Han sheep, Hu sheep and Texel, two genotypes (CC and CT) weredetected in White Suffolk. Sequencing revealed a C to T mutation in comparison genotypeTT with CC at330position of intron1of PROP1gene. The ewes with genotype TT or CThad0.83(P<0.05) or0.47(P<0.05) lambs more than those with genotype CC, and thedifference of the litter size between TT and CT genotypes was not significant（P>0.05）inSmall Tail Han sheep.