菲律宾蛤仔SRAP标记体系的建立及不同壳色品系的遗传学分析

Establishment of SRAP reaction conditions and the genetic analysis of three strains with different shell colors in Manila clam Ruditapes philippinarum

首次建立并优化了菲律宾蛤仔Ruditapes philippinarum SRAP分子标记技术体系,并利用17对引物组合对经过连续选育的白蛤、橙蛤和墨蛤3个菲律宾蛤仔品系进行了分子标记分析。结果表明:3个品系蛤仔共扩增出510个位点,白蛤品系的Nei指数和Shannon指数均显著高于墨蛤和橙蛤品系(P<0.05);遗传分化指数(Gst)为0.000 1～0.644 8,平均为0.046 7,表明有4.67%的变异存在于群体间,95.33%的变异存在于群体内;基因流(Nm)为0.275 4～2 000,平均每个位点的Nm为10.202 7;白蛤和墨蛤品系间的遗传距离最近(0.028 2),白蛤和橙蛤品系间的遗传距离最远(0.039 6)。研究结果表明,白蛤、橙蛤和墨蛤3个蛤仔品系间有很强的基因交流,遗传分化程度较弱,提示蛤仔品种的人工选育工作需持续进行。

A SRAP-PCR system was established and the genetic diversity were analyzed in Manila clam Ruditapes philippinarum with white（W）, black（B） and orange （O）shell colors through selective breeding by 17 pairs of SRAP primers screened from 36 primer combinations. A total of 510 loci were detected with 17 primer pairs, and Shannon＇s information index and Nei＇s gene diversity were found significant higher in W strain than those in B and O strain（P〈0.05 ） ,without significant differences between the last two strains. F-statistics（Gst） were varied from 0. 000 1 to 0. 644 8, with the mean value of 0. 046 7, indicating that 4.67% of variations were observed between B and O strains, and 95.33% of variations within the populations. The gene flow were found between 0. 275 4 and 2 000, with mean 10. 202 7 ,and genetic distances between 0. 028 2（W and B） and 0.039 6（ W and O）. The find- ings showed that there were weak genetic differentiations and strong gene flow among the three clam strains, and that the selective breeding for the clam was continued in order to establish new breeding. The 147 SRAP loci show- ing significant differences in frequency among the three strains（P〈0.05 ）, and the 82 SRAP loci showing very sig- nificant differences in frequency among the three strains（P〈0.01 ）, providing the foundation for explanation of the genetic basis of the good traits such as good growth, strong resistance and special shell colors in the three strains.