| In this paper, microsatellite DNA markers and PCR-RFLP technology were employed to detect the molecular genetic diversity of eleven microsatellite loci, DQA1 and DQA2 genes in five goat breeds, e.g. Laoshan dairy goat, Xinong Sannen dairy goat, Guanzhong dairy goat, Banjiao goat and Guizhou white goat. The genetic variability within populations and genetic relationships among them were discussed. Relationships between different genotype and body sizes, milk yields and litter sizes were analysed based on polymorphism. The study was aimed to provide scientific basis for proper development and protection of these goat breeds. The results were as followed:1. Eleven microsatellite loci were used to evaluate the genetic polymorphisms in five goat breeds.(1) Apart from BM203 and BM6425, the other nine loci were polymorphic and eighty-five alleles were detected, with a mean of 9.4, which indicted that the nine loci were more polymorphic in the five goat breeds.(2) Based on alleles, the average heterozygosity of overall loci and populations ranged from 0.6649 to 0.8379, 0.7313 to 0.8002, respectively. The nine loci were high polymorphic (PIC>0.5). This showed that there were great variability and broad genetic base in the five goat breeds.(3) Neutrality test was conducted on the nine loci in the five goat populations. Three microsatellite loci (BM315,BM1329 and TGLA68) was in confidence interval (95%) and on the contrary the other six loci were not neutral loci.(4) Heterozygosity in subpopulation, Total Heterozygosity, and coefficient of gene differentiation (Gst) of the nine microsatellite loci were calculated, which demonstrated small genetic differentiation between the five goat breeds. F-statistics of each microsatellite locus was analysed and the value of Fst and Nm ranged from 0.0304 (BM1329) to 0.1401 (BM315), 1.5351 to 7.9765 (the mean was 4.2998), respectively. (5) Genetic distance was calculated among the five goat breeds and UPGMA tree was constructed, which showed that the results were in accordance to their origin, history and geographical distribution.2. Relationships between microsatellite markers and two dairy goat breeds'production traits were analysed. The results were as followed:(1) The analysis result of growth trait showed the effects of breed were major effect. Some marker effects were found and the least square means were obtained.(2) The analysis result of milk yield and litter sizes showed the effects of breed were major effect in most indexs. No marker effects were found in the two dairy breeds.3. The genetic polymorphisms of DQA1 and DQA2 were detected by PCR-RFLP in five goat breeds. At the two RFLP loci of DQA1 gene, SN was moderate polymorphisms and the other four populations were low polymorphisms. Except GZ and LS, other three populations (SN, BJ and GW) were at Hardy-Weinberg equilibrium at Taqâ… -RFLP locus. At the Haeâ…¢-RFLP locus, the five populations were at Hardy-Weinberg equilibrium.There was no polymorphism at the DQA2 Pvuâ…¡-RFLP locus. At the DQA2 Haeâ…¢-RFLP locus, the five goat populations were not at Hardy-Weinberg equilibrium. Apart from SN with high polymorphisms, the other four populations showed moderate polymorphisms.4. The effects of genotypes of the two genes on the traits were analysed by linear model and there were not statistically significantly between the effects of genotypes and the traits. |
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