Study The Polymorphism Of Hircine Growth Differentiation Factor 9 Gene And The Relation Of Jining Grey Goat Prolificacy

Growth differentiation factor 9 (GDF9) gene is a growth factor secreted by oocytes in growthing ovarian follicles, which is essential for normal follicular development. Bsaed on the genetic polymorphism of GDF9 gene, we studied the genetic relationship between this candidate gene and the high reproduction ability of Jining grey goat. These researches provided scientific bases for the further genetic research on the high reproduction of Jining grey goat.The primers of exon 1 and 2 of hircine GDF9 gene were designed on base of the sequence of ovine GDF9 gene. After cloned and sequenced, the nucleotide of exon 1 of hircine GDF9 gene is 397 bp and is 99% (395 of 397) homologous to sheep. The nucleotide of exon 2 of hircine GDF9 gene is 965 bp and is 98% (955 of 965) homologous to sheep. The hircine GDF9 gene encodes a protein 453 amino acids and is 95%,92% , 76% homologous to sheep,cow and human, respectively.Applying the powerful PCR-SSCP technique to analyze the polymorphism of growth differentiation factor 9 gene, we found 3 pairs of primers of what we designed 6 pairs of primers have polymorphism. The products of primer 1 did not find polymorphism by SSCP, but detected one single nucleotide mutation(A→C) at encoding region -4bp by sequenced. The products amplified by primer 2 had polymorphism. The sequencing results indicated that there were two nucleotide mutations( C→A and C→T )at exon 1183bp and 336bp of hircine GDF9 gene, but the two mutations did not cause amino acid change. The products amplified by primer 3 had polymorphism. The sequencing results indicated that there was one single nucleotide mutation (G—A) at exon 2 26bp of hircine GDF9 gene, but this mutation did not cause amino acid change. The products amplified by primer 6 had polymorphism. The sequencing results showed that there was one single nucleotide mutation (G—A) at exon 2 792bp of hircine GDF9 gene, and this mutation resulted in an amino acid change: valine (Val)→isoleucine(Ile).The result of x ~2 fitness test of primer 2 indicated that Jining grey goat, Wendeng dairy goat, Liaoning cashmere goat, Beijing native goat and Boer goat all kept in Hardy-Weinberg equilibrium (P>0.05). The results of x~2 fitness test of primer 3 that Jining grey goat, Beijing native goat and Boer goat were high significantly biased from Hardy-Weinberg equilibrium (P<0.01), but Wendeng dairy goat and Liaoning cashmere goat were keep well in Hardy-Weinberg equilibrium (P>0.05). The results of x2 fitnesstest of primer 6 indicated that Jining grey goat was significantly biased from Hardy-Weinberg equilibrium(P<0.05), but Wendeng dairy goat, Liaoning cashmere goat, Beijing native goat and Boer goat were kept in Hardy-Weinberg equilibrium (P>0.05). The result of x 2 fitness test of primer 2 indicated that Jining grey goat with littering records kept in Hardy-Weinberg equilibrium (P>0.05). The results of x 2 fitness test of primer 3 and primer 6 indicated that Jining grey goat with littering records were high significantly biased from Hardy-Weinberg equilibrium (P<0.01).Among Jining grey goat with littering records, least squares analysis showed that the litter of AA and AB genotype is more 1.04 (PO.01) and 0.75 (P <0.05) than BB genotype, respectively. The litter of AA genotype is more 0.29 (P>0.05) than AB genotype. The litter of CC genotype is more 0.54 (PO.05), 0.63(P<0.05) than CD and DD, respectively. The litter of CD genotype is more 0.09 (P>0.05) than DD genotype. The litter of EE genotype is more 0.57 (PO.05), 0.62(P<0.05) than EF and FF, respectively. The litter of EF genotype is more 0.05 (P>0.05) than FF genotype. According to all of our results, we conclude that the polymorphism of fragments amplified by three pairs of primer probably associate with Jining grey goat productive trait, but need further studies.