华北2蝗区东亚飞蝗种群遗传结构的比较研究

利用水平淀粉凝胶电泳对采自天津北大港和河北黄骅两个相临蝗区的东亚飞蝗（Locusta migratoria manilensis)种群进行等位酶基因频率分析，比较了这两个种群的遗传结构，等位酶酶谱分析表明，19个基因座中4个基因座（Mdh-l,Pgm,Adk,G3pd)的等位基因频率变化很小，常见等位基因的频率均高于0．95，其他基因座有2－4个等位基因，但是两个种群的等位基因频率除两个基因座（Fbp,Got-2)外都很相似，多态位点的27个χ2检验表明，由于常见等位基因纯合子的高频率的和相应杂合子的缺乏，仅有北大港种群的2个基因座（Pgi,Got-1)符合Hardy-Weinberg平衡，在每个种群内的蝗虫存在明显的遗传变异，但在种群间遗传结构极为相似，多态位点的百分数P分别为73．7％和78．9％，每个基因座的平均等位基因数A为2．9和3．1，平均每个基因座的实际杂合度几乎相等（约为0．138），F－统计量（FST＝0．053）也表明了两个种群间的遗传 一致性，遗传相似性系数（I）高达0．938，这些结果提示，这两个种群可能属于1 个大种群，在两个种群的一定位点上的遗传多态性和分化可能都与迁飞因素有关，因为东亚飞蝗的高度扩散能力有利于遗传结构的连续分布，高度的迁飞能力也导致个体暴露于各种不同的环境，而在种群水平上的遗传为异能增强种群在各种生态条件生存和繁殖能力，因此，迁飞有利于维持东亚飞蝗种群的遗传多态性的动态平衡。

Comparative Allozyme Analysis of Oriental Migratory Locust Locusta migratoria manilensis from Two Breeding Areas in North China

The allozyme analysis using horizontal starch gel electrophoresis was employed to compare the genetic structure in the populations of oriental migratory locust Locusta migratoria manilensis from two breeding areas,Beidagang(Tianjin) and Huanghua(Hebei). The two areas are adjacent but with distinct ecological features,with the recorded locust outbreaks and migration. The zymograms showed that among nineteen loci four (Mdh-1,Pgm,Adk and G3pd) showed extremely low variability level with the frequency of the most common allele higher than 0.95 in the populations from both sites. The rest loci had 2 to 4 alleles but the allele frequencies between the two populations were all similar except Fbp and Got-2 loci. In the 27 χ2-tests for the genotypes at polymorphic loci only two (Pgi and Got-1) of Beidagang population did fit the Hardy-Weinberg's expectations. This is due to high frequencies of the most common homozygotes and the corresponding heterozygote deficiency. The allozyme data demonstrated that the locusts had remarkable genetic variability withineach population,but little divergence between the populations. The genetic variability measurements were found similar:Percentage of polymorphic loci (P) was between 73.7% and 78.9%;The mean number of alleles per locus (A) was from 2.9 to 3.1;and the mean heterozygosity (Ho) was nearly identical (about 0.138). The F-statistics (FST=0.053) also showed the genetic uniformity of the populations,corresponding to the high Nei's genetic identity (I=0.938). These results of the allozyme analysis suggested that the two populations appeared to be a part of a large population. It is reasoned that the genetic polymorphism and differentiation at certain loci between the two populations may depend on at least two agnostic factors that are all related to migration. First,the unusual dispersal capability of L.m.manilensis tends to make a continuous genetic structure distribution. Second,the frequent migration also results in the individuals to be exposed to drastically various environments. Since the broad adaptability is crucial to survive the changing environments,the genetic variation at population level is necessarily required to offer the population resilience for successful survival and reproduction under those ecologically divergent abiotic and biotic conditions. Thus,the migration contributes to the maintenance of dynamic equilibrium of genetic polymorphism in this highly specialized subspecies.