Genetic Analysis Of GH, MSTN And GHR Genes And Their Associations With Growth Traits In Goats

In this experiment, PCR-SSCP and DNA sequencing techniques were applied to analyze the genetic variation of GH gene (exon1～5, 5'UTR ), MSTN gene(exon1～3 and intron2), GHR gene (exon 4,9 and 10) in Boer goat and its hybridized offspring with Guanzhong dairy goat and Sannen goat. The objective was to detect the hereditary characteristics and its associations with some growth traits (body weight, withers height, body length, heart girth and circumference of cannon bone),and to explore molecular markers with significant effects on economic important traits for efficient selection and improvement of Boer goat and its hybridized offspring and Sannen goat , and to provide genetic information for construction of molecular marker database, protection and utilization of breed resource of goat. The results were as follows:1. Associations of polymorphisms of 5'regulated region goat GH gene and growth traits.There were AA, AB and BB three genotypes in GH gene 5'regulated sequence, and a mutation of A>C located in 27bp AB genotype of GH gene. The A allele was dominated in this loci, the Boer and F1 hybrid goat population was at Hardy-Weinberg unbalance (P<0.05) There was significant difference between the genotypes for growth trait in F1 and F2 (P<0.05). At F1 hybrid,the trend of"AB>AA"was observed in the traits of body height and"BB>AA"was observed in the traits of withers height at 1, 2 month(P<0.05), the trend of"AB>AA"was observed in the traits of body length at 1, 3 month(P<0.05).At F2 hybrid, the trend of"BB>AB"was observed in the traits of body height and withers height at 1 month, and"BB>AB"was observed in the traits of body height at 2 month (P<0.05).The result showed that there were significantly effect at 5'regulated region of goat GH in weight and withers height traits.2. Associations of polymorphisms of Ex3 locus goat GH gene and growth traits.There were six genetic variations and five genotypes (AA, AB, BC, CD and BD) at Ex3 locus in the study populations, but AB and CD wee not detected in F3 hybrid. A mutation of A>G located in 161bp of BD genotype result in Glycine to Serine; In this loci .A allele was dominated genotypes and the population except sannen goats was at Hardy-Weinberg balance (P>0.05) There were genetic variation at Ex3 locus(PIC>0.5).The association of genotypes and growth traits was significant in the study population. The body weight, withers height and body length of AA, AB genotype were significantly higher compared with other genotype (P<0.05).3. Associations of polymorphisms of Ex5 locus goat GH gene and growth traits.There were AA,AB,AC and AD four genotypes and two genetic variations at Ex5 locus in the study populations. A mutation of C>T located in 237bp of AB genotype and C>A located in 289 bp of AD genotype were detected. The two mutations were silence and have genetic variation in Boer and F3 (0.25AC"was observed in the traits of body length at1,2 and 3 month(P<0.05). At F2 hybrid the trend of"AB>AC"was observed in the traits of body weight at 1 month (P<0.01). The result showed that there was significantly effect at Ex5 locus of goat GH in weight and withers height traits.4. Associations of polymorphisms of Ex1 locus goat MSTN gene and growth traits.There were AA and AC two genotypes at Ex1 locus and a mutation of A>C located in 216bp of AC genotype was detected. In the study populations AA was dominated genotypes and all populations except sannen was at Hardy-Weinberg balance (P>0.05). At F1 hybrid the trend of"AC>AA"was observed in the traits of body weight at 2 month (P<0.05). At F2 hybrid the trend of"AC>AA"was observed in the traits of heart girth at 2 month (P<0.05).5. Associations of polymorphisms of Ex3 locus goat MSTN gene and growth traits.There were AA and AB two genotypes at Ex3 locus. In this loci A allele was dominated genotypes and the study population was at Hardy-Weinberg balance (P<0.05) There were no genetic variation in the study population and the association between genotypes and growth traits were no significant in Boer and F1 (P>0.05). At F2 hybrid the trend of"AB>AA"was observed in the traits of heart girth at 3 month (P<0.05). At F3 hybrid the trend of"AB>AA"was observed in the traits of withers height at 3 month (P<0.05).6. Associations of polymorphisms of Ex9 locus goat GHR gene and growth traits.There were AA and AB two genotypes at Ex9 locus of GHR gene and a mutation of T>G located in 237bp of AB genotype was detected the population Boer and F3 goats was at Hardy-Weinberg balance (P>0.05) There have higher genetic variation in Boer and F3 and the association between genotypes and growth traits was no significant difference in Boer and F3 (P>0.05). At F1 hybrid the trend of"AB>AA"was observed in the traits of heart girth at 3 month (P<0.05).At F2 hybrid the trend of"AB>AA"was observed in the traits of body length at 3 month (P<0.05).