| The cost of developing replacement nanny goats could be reduced by decreasing age at puberty because nanny goats can be brought into production at earlier age. Jining Grey goat is a sexual precocious breed.The aim of the current research was to find new genes associated with sexual precocity of goat and understand the mechanism of action, and provide some useful information for the molecular breeding to shorten the timing of puberty of goat.1. According to Bos taurus UBA52gene sequence, three pairs of primers (Ul to U3) were designed to clone goat UBA52and scan polymorphisms and one pair of primers to detect polymorphisms of UBA52in sexual precocious and high fecundity goat breeds (Jining Grey, Nanjiang Brown and Matou goats) and sexual late-maturing and low fecundity goat breeds (Liaoning Cashmere, Inner Mongolia Cashmere and Taihang goats) by PCR-RFLP. The results showed that there were only two base changes (G63A and T181C) in the product amplified by primer U3. For the63locus, three genotypes (GG, GA and AA) were detected in Jining Grey and Nanjiang Brown goats, only two genotypes (GG and GA) were in Matou, Liaoning Cashmere, Inner Mongolia Cashmere and Taihang goats. There were certain differences in genotype distribution between the sexual precocious and sexual late-maturing goat breeds. In Jining Grey goats, the frequency of genotypes GG, GA and AA was0.53,0.44and0.03, respectively. And the Jining Grey goat does with genotype AA and GA had0.85(P<0.05) and0.49(P<0.05) kids more than those with genotype GG, respectively. No significant difference (.P>0.05) was found in litter size between AA and GA genotype in Jining Grey goats. For the181locus, three genotypes (CC, CT and TT) were detected in Nanjiang Brown and Inner Mongolia Cashmere goats, only two genotypes (CC and CT) were in the other four goat breeds. No significant difference was found in genotype distribution between the sexual precocious and sexual late-maturing goat breeds. In Jining Grey goats, the frequency of genotypes CC and CT was0.91and0.09, respectively. And there was no significant difference (P>0.05) in litter size between the only two genotypes CC and CT in Jining Grey goats. The present study preliminarily indicated that there may be some association between63locus of UBA52gene and sexual precocity in goats, and allele A of UBA52gene is a potential DNA marker for improving litter size in goats.2. According to Bos taurus GDH1gene sequence, seven pairs of primers (PI to P7) were designed to clone goat GDH1and scan polymorphisms and one pair of primers to detect polymorphisms of GDH1in sexual precocious and high fecundity goat breeds (Jining Grey, Nanjiang Brown and Matou goats) and sexual late-maturing and low fecundity goat breeds (Liaoning Cashmere, Inner Mongolia Cashmere and Taihang goats) by PCR-RFLP. The results showed that there was only one base change (A197C) in the product amplified by primer P6. For the197locus, only two genotypes (AA and AC) were detected in Nanjiang Brown goats, while three genotypes (AA, AC and CC) were in the other five breeds. There were certain differences in genotype distribution between the sexual precocious and sexual late-maturing goat breeds. In Jining Grey goats, the frequency of genotypes AA, AC and CC was0.69,0.26and0.05, respectively. And the Jining Grey goat does with genotype AA had0.54(P<0.05) and0.3(P<0.05) kids more than those with genotype CC, respectively. No significant difference (P>0.05) was found in litter size between AC and CC genotype in Jining Grey goats.The present study preliminarily indicated that there may be some association between197locus of GDHl gene and sexual precocity in goats, and allele A of GDH1gene is a potential DNA marker for improving litter size in goats.3. This research was study on30±5,90±5days in female sexual precocious goat breed Jining Grey goat and30±5,90±5,160～180days in female sexual late-maturing goat breed Liaoning Cashmere goat.We used real-time PCR technology to exam the mRNA expression of UBA52and GDHl genes in hypothalamus, pituitary gland, ovary, uterus and adrenal gland, aimed to know the association between the genes and sexual precocity of goats. Quantitative results showed that:UBA52gene expressed in the five tissues of different developmental stages, and the uterus expression level was very significantly higher than the other four tissues (P<0.01). The pituitary gland expression level in puberty was very significantly lower than in juvenile period of Jining Grey goat (P<0.01), while the expression level in juvenile period Ⅱ was very significantly higher than in juvenile period I of Liaoning Cashmere goat,and it in puberty was very significantly lower than in juvenile period Ⅱ (P<0.01). GDHl gene also expressed in the five tissues of different developmental stages, and the hypothalamus expression level was higher than the other four tissues except in puberty of Liaoning Cashmere goat.The ovary expression was very significantly higher in puberty than in juvenile period (P<0.01) The results showed that the pituitary gland expression level of UBA52and the ovary expression level of GDHl may have an effect on the puberty of goat. |
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