中国对虾家系水平遗传多样性的AFLP分析

AFLP analysis of family level genetic diversity of shrimp Fenneropenaeus chinensis

采用扩增片段长度多态性分子标记技术对中国对虾的40个家系共200个样品进行了家系水平的遗传多样性分析。利用10对引物共产生307个表达清晰可用于分析的标记,其中189个标记表现为多态性,占总标记数的61.56%;中国对虾各个家系多态位点百分率在12.7%～34.2%之间;各个家系基因多样性指数在0.0494～0.122之间,Shannon指数的范围在0.0725～0.182之间(家系水平为0.1975)。对40个家系的AMOVA分析结果显示,家系间的基因分化系数Gst=0.4713,即总的遗传变异中有47.13%的变异存在于家系间,家系内的遗传变异占总遗传变异的52.87%。采用UPGMA法对中国对虾的40个家系进行了聚类分析,确定了各个家系之间的遗传亲缘关系;并且对200个个体进行了聚类分析。结果表明,90%同一家系的子代个体能完全聚类在一起。通过家系间的遗传分化系数Gst对中国对虾的40个家系间的基因流进行了估测,结果显示,Nm=0.5609,表明基因流处于较低水平。

Amplified fragment length polymorphism（AFLP）technique was used to detect the genetic variation among a total of 200 individuals representing 40 families.Popgene version 1.32,MEGA3.1 and AMOVA in Alequin 2.0 software were used for data analysis.Ten pairs of selective EcoRⅠ and MseⅠ primers produced 189 polymorphic markers out of total 307 bands amplified;the percentage of polymorphic loci was 61.56%.The percentages of polymorphic loci of the forty families were between 12.7% and 34.2%.Genetic diversity index of the families were between 0.049 4~0.122,and Shannon genetic diversity index were between 0.072 5 and 0.182（intra-family index was 0.197 5）.AMOVA（Analysis of molecular variance）showed that a large proportion（52.87%）of genetic variation resided within families,while only a small proportion（47.13%）of genetic variation resided between families,representing an inter-family genetic differentiation index of Gst=0.471 3.Cluster analysis by UPGMA revealed the genetic distance and relationship between the 40 families,and the UPGMA dendrogram of the 200 individuals indicated that 90% of the individuals from each family could be fully clustered.Genetic diversity index G-based estimation revealed a low gene flow（Nm=0.560 9）among the 40 families.