中国东亚飞蝗两个种群遗传分化的研究

采用水平淀粉凝胶电泳技术，分析了我国河北平山、辽宁葫芦岛两个蝗区东亚飞蝗自然种群的遗传结构。在酶谱分析的19个位点中，多数位点的等位基因数目较少，而位点Aat—l、Pgi和Mdh—2的等位基因数目相对较多。由于杂合子数目较少而使每个基因位点的平均杂合度降低(Ho=0．024和0．028)。对每个位点的各基因型进行x^2检验，绝大多数位点的基因型频率偏离Hardy—Weinberg平衡。较低的Fst值(Fst=0．021)表明两个种群的遗传分化程度不高。两个种群间较高的遗传一致度(I=0．991)和较小的遗传距离(D=0．092)也证实了上述结果。由此推测，该蝗虫较强的迁飞能力有可能增强种群间的基因交流，降低种群间的遗传分化。然而，在一些等位酶指标如位点Ao-2、Fbp—l、Mdh—2的等位基因频率分布、每个位点的平均等位基因数(A=2．5和2．7)和多态位点百分率(P=52．6％和57．9％)等，两个种群之间呈现出明显的差异。这也许与两个种群之间不同的生态环境条件和较远的地理距离有关。

Studies on the Genetic Differentiation of Two Populations of Oriental Migratory Locusta migratoria manilensis in China

The genetic structure of two populations of the oriental migratory locust Locusta migratoria manilensis (Meyen) from Hebei and Liaoning in China was analyzed by horizontal starch gel electrophoresis.Among 19 loci of 13 enzymes identified in zymograms,most loci had low variability with a few alleles.In contrast,high polymorphism was observed at Aat 1,Pgi and Mdh 2. Lower observed overall heterozygosity ( Ho =0 024 and 0 028) was found in both populations due to heterozygote deficiency.Chi square test for the genotype frequencies at each locus,the genotype frequency of the most loci deviated from Hardy Weinberg equilibrium.The extremely low F st values revealled small genetic differentiation between the two populations ( F st =0 021).Higher genetic identity ( I ) and smaller genetic distance ( D ) also testified the above result ( I =0 991; D =0 092).It is reasoned that the migration could enhance gene flow and decrease genetic differentiation among populations.However,the obviously variations were found in the distribution of allele frequency at loci Ao 2,Fbp 1,Mdh 2 ,the number of allele ( A =2 5 and 2 7) and the percentage of polymorphic loci ( P =52 6% and 57 9%),which might be related to the different habitat conditions and farther geographic distance between the two populations.