中华稻蝗四个种群的遗传分化

采用水平淀粉凝胶电泳技术研究中华稻蝗(Oxyachinensis)四个种群的12个基因座位,探讨其遗传分化.这四个种群分别采自内蒙古呼和浩特、山西代县、山西太原和陕西西安.Ck和Mdh-2在四个种群中均为单态,其余的基因座位至少在一个种群内有两个以上的等位基因;在Ldh和Mdh-1的等位基因频率呈现梯度分布趋势.多态基因座位百分率(P)和平均每个基因座位的等位基因数目(A)分别为58.3%-66.7%和2.2-2.8,平均杂合度为Ho=0.173-0.240.除Gpi,Hk-2,Idh,Ldh和Mdh-1在部分蝗虫种群符合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Hardy-Weinberg平衡.四个种群间FST平均值不存在显著差异(FST=0.0510,P＞0.05),结合高的Nei's遗传一致度(I＞0.97)可知,种群之间遗传分化不明显.我们认为人类的农业活动可能促进了种群间的基因交流,从而降低了分化程度[动物学报50(2)187-192,2004].

Genetic differentiation among four populations of Chinese rice grasshopper Oxya chinensis in China

Twelve loci (Ak, Ck, G3pdh, Gpi, Hk-1, Hk-2, Idh, Ldh, Mdh-1, Mdh-2, Mdhp and Pgm) were examined using horizontal starch gel electrophoresis to study the genetic differentiation among four populations of Oxya chinensis in China. The collecting sites were geographically distant each other, i. e. (1) Hohhot, Inner Mongolia; (2)Daixian, Shanxi; (3) Taiyuan, Shanxi and (4) Xi'an, Shaanxi. Mdh-2 and Ck were monomorphic whereas more than one alleles were present at the remaining loci. A dinal tendency in allele frequency was observed at two loci of Mdh-1(0.754- 0.956) and Ldh (0.508- 0.852). The O. chinensis population showed relatively high percentage of polymorphic loci ( P = 58.3 % - 66.7 % ), the mean number of alleles per locus ( A = 2.2 - 2.8) and heterozygosities ( Ho =0.173- 0.240). The genotype frequency at most loci significantly deviated from the Hardy-Weinberg equilibrium except for Gpi, Hk- 2, Idh, Ldh and Mdh- 1 in several populations. The overall FST was not significantly different from zero (overall FST = 0.0510, P ＞ 0.05). Along with the high Nei' s genetic identity ( I ＞ 0.97), the data indicated less divergence among the four populations. We propose that human agricultural activities might have mediated the gene exchange among the grasshopper populations and thus reduced the differentiation level [Acta Zoologica Sinica 50 (2): 187 - 192,2004].