山西省8种蝗虫8个种群的遗传学研究

采用水平淀粉凝胶电泳技术，对采自山西省蝗虫区系的优势种类；斑腿蝗科（Catantopidae），斑翅蝗科（Oe-dipodidae）和网翅蝗科（Arcypteridae）3科7属8种蝗虫的11种酶进行了检测，共辨析出17个酶基因座位，并计算出等位基因频率和遗传距离，等位基因频率分析表明：Ao-I、Est-3,G3pd-1、Idh-2和Mdh-2基因座位的等位基因少，等位基因数目在种间变化较小，故推断其进化速率较慢，利用这些基因座位的保守特征，可作为分子标记研究较高级阶元的系统发育关系，而Gpi-1，Ldh-1和Me-1基因座位的等位基因多，等位基因数目在种内和种间差异较大，可以用作种，属间及种群间遗传结构的比较研究。对每个基因座位的各基因型进行χ^2检验，除Acp-1,Adk-1,Ao-1和Ao-2在部分蝗虫中符合Hardy-Weinberg平衡外，其余绝大多数基因座位的基因型频率显著偏离H-W平衡。在所研究的8种蝗虫中，多态位点百分率普遍较高（P=64.7%～94.1%），但由于杂合子数目较少而使每个基因座位的平均杂合度降低（Ho=0.024～0.087），对多态位点百分率分析发现：迁飞能力是影响蝗虫种间遗传变异的因素之一，具有迁飞能力的蝗虫（P=88.2%～94.1%）较非迁飞性蝗虫（P=64.7%～94.1%）表现出较高的遗传多态性，但也有例外，如中华稻蝗（Oxya chinensis）的P值高达94.1%，上述结果表明：由于迁飞行为可使个体暴露于各种不同环境，故而种群保持较高的遗传多态性能增强该物种在不同栖息地的生存和繁殖能力，因此，迁飞有利于维持迁飞性蝗虫遗传多态性的动态平衡。根据Nei的遗传一致度（I）和Roger的遗传距离（D）进行分析，结果与基于形态特征确定的分类阶元系统关系基本相符；即同属的小翅雏蝗（Chorthippus fallax）和白纹雏蝗（Chorthippus albonemus）具有最高的遗传一致度（I=0.813）和最小的遗传距离（D=0.336），同位不同属间遗传一致度（I=0.798～0.559）和遗传距离（D=0.398～0.474）居中，科之间I值最小（I=0.523～0.479），D值最大（D=0.505～0.523），利用UPGMA对I值和D值进行聚类，所得两种聚类图在同属种间和同科属间的关系一致，但在科间关系有所差别，Roger的遗传距离（D）聚类树图表明：斑腿蝗科物种和斑翅蝗科物种间表现出较小的遗传距离（D=0.505），而网翅蝗科与以上两科的遗传距离也极为接近（D=0.523），综上所述，等位酶分析能较好地反映蝗虫同属种间和同科属间的亲缘关系，若能断更高阶元的系统发生，则需结合其他性状进行综合分析。

Genetic Studies on Eight Populations of Eight Locust Species from Shanxi Province, China

The genetic structure of eight locust species in three families ( Catantopidae, Oedipodidae and Arcypteridae) from Shanxi Province in China was compared using allozyme analysis with horizontal starch gel electrophoresis. Among 17 loci identified in zymograms, Ao-1, Est-3, G3pd-1, Idh-2 and Mdh-2 had low variability with a few alleles. High polymorphism was observed at Ldh-1, Me-1 and Gpi-1. Each of the eight species demonstrated high percentage of polymorphic loci (P = 64.7 % ～94.1% ) but low observed heterozygosity ( Ho = 0. 024 ～ 0.087) due to heterozygote deficiency. It was noted that the migratory locusts usually had higher percentage of polymorphic loci ( P = 88.2 % ～ 94.1% ) than non-migratory species ( P = 64.7 % ～ 94.1% ). The only exception is Oxya chinensis ( P = 94.1% ). It is reasoned that the higher polymorphism is necessary for migratory species to cope with the environments that might be drastically different from the habitats before migration. The taxon relationships using cluster analysis based on Nei's genetic identity (I) and Roger's genetic distance (D) were the same at species and genus levels. The differences were found at family level, possibly due to the alternative algorithms. The cladogram using Roger' s genetic distance (D) overlapped the relationship obtained from karyotypic analyses, which demonstrated that the species examined in Catantopidae displayed somewhat closer relationship to those in Oedipodidae than to those in Arcypteridae. It is suggested that the allozyme analysis is useful as molecular marker for locusts in phylogenetic reconstruction at the species and genus level, while additional data from other studies are necessary when used for higher taxa.