Study On Bone Morphogenetic Protein Receptor IB As A Candidate Gene For Fecundity In Several Sheep Breeds In Xinjiang

BMPR-IB gene as a fecundity candidate gene was studied in Cele sheep(44 blood samples), Duolang sheep(49 blood samples), Hu sheep (32 blood samples),Chinese Merino(Xinjiang type) monotocous line(40 blood samples) and Chinese Merino(Xinjiang type) (47 blood samples) by PCR-RFLP. The results showed that there was a mutation of A → G in BMPR-IB gene in Cele sheep,Duolang sheep,Chinese Merino(Xinjiang type) monotocous line and Hu sheep,which were the same as in Booroola Merino ewes.The mutation was not identified in Chinese Merino(Xinjiang type). Among them, the BB,B+ and ++ frequences in Cele sheep were 0.16, 0.48 and 0.36 respectively. There was no BB genetype in Duolang sheep, in which the B+,++ frequences were 0.65 and 0.35 respectively. The BB were dominent in Hu sheep and BB frequence was 0.97. The B+ were dominent in Chinese Merino(Xinjiang type) monotocous line and the BB, B+ and ++ frequences were 0.05, 0.7 and 0.25 respectively. Analysis of litter size showed that Chinese Merino(Xinjiang type) monotocous line with genotype BB had more litter size than those with genotype B+ or ++ (P<0.01). The chi-sequare test(x~2) showed that ,for BMPR-I B Q249R mutation, the populations of Cele sheep ,Duolang sheep, Chinese Merino and Hu sheep were in a state of Hardy-Weinberg Equilibrium(p>0.05).However the Chinese Merino(Xinjiang type) monotocous line population was not in a state of Hardy-Weinberg Equilibrium (p<0.05). These results showed that BMPR-IB gene was a major gene for prolificify in Chinese Merino (Xinjiang type) monotocous line. The distribution of BMPR-IB genotype was significantly different (P<0.001) between Chinese Merino(Xinjiang type) and other sheep breeds. The same phenomenon also existed between Duolang sheep and Chinese Merino(Xinjiang type) monotocous line(P<0.01), as well as between Hu sheep and Cele sheep, Chinese Merino(Xinjiang type) monotocous line .Duolang sheep(P<0.001).Because the PCR-RFLP is time and cost-consuming,which involved restriction endonuclease digestion of PCR products, the study established Tetra-primer ARMS-PCR technique to detect BMPR-IB gene in Cele sheep and Duolang sheep. The results were consistent with PCR-RFLP detection and indicated that the Tetra-primer ARMS-PCR was feasible,reliable,simple,rapid and cost-consuming for detecting BMPR-IB mutation and other SNP locus.