Studies On Polymorphism Of BMP4 BMP15 Gene And Its Correlation With Litter Size In Sheep Populations

In this study, we choose bone morphogenetic protein 4 and bone morphogenetic protein 15 as the candidate gene. Genetic variation of bone morphogenetic protein 4 (BMP4) gene sequence was analyzed by PCR-SSCP,and that of BMP15 by PCR-RFLP、PCR-SSCP methods in Small Tailed Han Sheep, Poll Dorset sheep, and their F1 hybrid sheep and F2 hybrid sheep, statistical analyzed the relationship between the sites of different genotypes and litter size. We aimed to obtain the corresponding molecular genetics information in different sheep breeds, verify the genetic features of bone morphogenetic protein 4 and bone morphogenetic protein 15, and provide an effective molecular marker for the assisted selection about the high prolificacy traits sheep and provide the basis for selection crossbreeding technology about multiple births meat sheep. We detect the single nucleotide polymorphism of BMP15 FecXG sits by PCR-RFLP and PCR-SSCP technology in 402 of four different sheep breeds such as Small Tailed Han sheep, Poll Dorset and the hybrid generation of Small Tailed Han sheep and Poll Dorset. The results showed that the B2 Mutation was not detected in that four sheep groups as it was detected in Belclare and Cambridge. It showed that the natural incidence of B2 Mutation of BMP15 was very low in that four sheep breeds.The single nucleotide polymorphism of BMP4 gene was detected by PCR-SSCP in 335 of four different sheep breeds such as Small Tailed Han ewes. The results indicated that the allele frequency of B and + in Small Tailed Han Sheep were 0.167 and 0.833, genotype frequency of BB, B+ and ++ were 0.010, 0.297 and 0.692, the allele frequency of B and + in Poll Dorset were 0.404 and 0.596 ,genotype frequency of BB, B+ and ++ were 0.000, 0.808 and 0.192; in F1 hybrid sheep, allele frequency of B and + were 0.250 and 0.750, genotype frequency of BB, B+ and ++ were 0.053,0.394 and 0.553; in F2 hybrid sheep, allele frequency of B and + were 0.025 and 0.975, genotype frequency of BB, B+ and ++ were 0.000, 0.050 and 0.950.The average litter size of B+,++ type was 1.84±0.57 and 2.33±0.60,the average litter size of B+ more than that of ++ type was 0.49 in Small Tailed Han Sheep with littering records,theχ~2 test showed that the difference was extremely significant (P﹤0.01), the litter size of Small Tailed Han Sheep has closed relationship with the mutation of 305 sits. the average litter size of ++, B+ and BB of F1 generation were 2.00±0.00, 2.23±0.43 and 2.00±0.00,and the difference of ++, BB and B+ was significant (P<0.05) ; futher showed that the relationgship.gene B can’t increase the litter size of Dorset sheep.