中国桔小实蝇种群的微卫星多态性分析

为了研究桔小实蝇种群的遗传结构，本文采用微卫星分子标记技术，对中国南方9省区、越南和泰国的11个桔小实蝇地理种群共224个个体的遗传多样性水平及种群遗传结构进行了研究。用9对微卫星引物共检测到48个等位基因, 平均每个微卫星位点的等位基因数为5.33个。GENEPOP分析结果表明：11个桔小实蝇种群在9个微卫星位点上的多态位点百分率平均为94.45%。种群的Nei's基因多样性指数平均为0.4371，Shannon信息指数平均为0.7870，表明桔小实蝇种群具有非常丰富的遗传多样性。Nei's遗传多样性分析发现，各地理种群间产生了一定程度的遗传分化，种群间平均遗传分化系数F_st=0.2370。种群间一定程度的遗传分化可能是由地理隔离和基因流障碍（N_em = 0.8049）所引起。UPGMA聚类分析可知， 中国的桔小实蝇地理种群可分为华南支和西南支两大分支，华南分支包括福建、台湾、广东和海南4个种群，西南分支包括四川、云南、广西、贵州和湖南5个种群。由此推测, 中国桔小实蝇种群结构的形成与演变是在地理演化与经贸交流加强这两种因素的影响下不断进行的动态过程。

Microsatellite polymorphism of Bactrocera dorsalis (Hendel) populations in China

The genetic diversity of 11 Bactrocera dorsalis (Hendel) populations consisting of 224 individuals collected from 9 provinces of South China, Vietnam and Thailand was investigated using simple sequence repeat (SSR) markers to study the genetic differentiation among populations. Total 48 alleles at nine loci were amplified, with average of 5.33 alleles each locus. A relatively high level of genetic diversity was revealed: P=94.45%, Nei's=0.4371, I=0.7870. A higher level of genetic differentiation was detected among populations with Nei's F-statistics, F_st=0.2370. The differentiation in certain degree may result from geographical isolation and barriers to gene flow. UPGMA cluster analysis indicated that the 9 populations from China clustered in two clades, the Southern China clade and the South-western China clade. Populations from Fujian, Taiwan, Guangdong and Hainan gathered into the Southern China clade, while populations from Sichuan, Yunnan, Gaungxi, Guizhou and Hunan formed the South-western China clade. It was so inferred that the evolutionary processes of the populations of the Oriental fruit fly in China are influenced by two factors, i.e, geographical divergence and gene flow by trade communication.