Polymorphisms And Bioinformatic Analysis On Exon 1 And Exon 2 Of The Changjiang Delta White Goat Growth Differenciation Factor 9 Gene

Growth differentiation factor 9(GDF-9) is a breed-specific hormone,which is secreted by oocytes and can support follicle growth and oocytes development,and facillitate the formation of corpus luteum at the late stage of ovulation cycle.This research used PCR-SSCP to detect the genetic polymophism of GDF-9 gene exon 1 and 2 in Changjiang Delta White goat,Huanghuai goat and Boer goat up to 187 individuals.Moreover,the ralationship between polymorphic sites and goat litter size was also analyzed in order to study the gene sites controlling goat reproduction,which will provide theoretical basis for selection and preservation of Changjiang Delta White goat.Furthermore,the amino acid composition,sequence characteristics of GDF-9 gene were analyzed by bioinformatics software assay.In addition,the structure and fuction of GDF-9 protein were predicted. Results are as follows:1.PCR-SSCP analysis of goat GDF-9 gene exon 1 and 26 fragments were amplified and mutations were found in 3 of them.There were three genotypes(AA,AB and BB) with primer 2 products;and 4 genotypes(CC,CD,DD and CE) with primer 5 products;and 4 genotypes(GG,GH,HH and GI) with primer 6 products.The sequencing results demonstrated:a point mutation(183 bp C→A) was found in exon 1, which was a silence mutation;4 mutations were found in exon 2.Among them the mutation of 421 bp C→T results in the change of Ala→Val,the mutation of 562 bp A→C results in the change of Gln→Pro,the mutation of 791 bp G→A is a silence mutation,and the mutation of 792 bp G→A results in the change of Val→Ile.2.Group Genetic analysis of goat GDF-9 gene and its relation with goat reproduction characteristicsGenetic analysis showed:In primer 2 products,AA AB and BB were existent in all the three goat breeds.Changjiang Delta White goat was mostly AB genotype,and Huanghuai and Boer goat were mostly AA genotype.A allele frequency was the highest in all of the three breeds.In primer 5 products,CC CD and DD were existent in all of the three goat breeds,and CE genotype only existed in Changjiang Delta White goat.Huanghuai and Boer goat were mostly CC genotype.C allele frequency was the highest in all of the three breeds. In primer 6 products,GG and GH were existent in all of the three goat breeds,HH was existent only in Huanghuai goat,GI existed in Changjiang Delta White goat and Boer goat. Changjiang Delta White goat and Boer goat were mostly GG genotype,and Huanghuai was mostly GH genotype.C allele frequency was the highest in all of the three breeds. Group-equilibrium tests showed:the value was not significantly different in goat GDF-9 gene exon 2 primer 5 and 6 in the three breeds,which was in Hardy-Weinberg equilibrium(P＞0.05).This demonstrated these two sites were not affected by artificial selection.But there was a significant difference in Boer goat in primer 2 products of exon 1. while no difference in other two breeds.Maybe this was because of the few samples of Boer goat.Least squares analysis of the polymorphicsits and reproduction characteristics showed: For primer 2 products,there was no significant difference between the three genotypes.For primer 5 products,AA genotype had 0.054 more litter size than AB genotype(P＜0.05),and BB genotype had 0.167 more litter size than AB genotype(P＜0.01).There was no significant difference between AA and BB genotypes(P＞0.05).For primer 6 products,there was also no significant difference between genotypes.3.Bioinformatics Analysis of the goat GDF-9 GeneThe amino acid composition,subcellular location and amino acid sequence character were analyzed by bioinformatics software assay,and the structure and ruction of GDF-9 protein were also predicted.