【摘要】 用等位酶电泳分析方法对短额负蝗(A tractom orpha sinensis)和奇异负蝗(A tractom orpha p ereg rina)各3个自然种群10种酶(AAT,CK,G 3PD,HEX,IDH,LDH,M DH,M E,PG I,PGM)进行检测。结果显示:两种负蝗在某些基因座上共享常见的等位基因,如A a t-1-b、A a t-2-b、G 3p d-a、Ck-1-b和Ldh-b;除个别基因座在部分种群符合H ardy-W e inberg平衡外,两种负蝗的大多数基因座的基因型频率显著偏离H ardy-W e inberg平衡。此外,奇异负蝗M e-c(0.318~0.740)、短额负蝗H ex-1-a(0.800~1.000)及Ldh-b(0.487~0.750)等位基因频率呈现出由北向南递增的趋势,表明M e和H ex、Ldh基因座上的等位基因频率与地理分布存在一定的相关关系。短额负蝗平均每个基因座的等位基因数(A)为1.9~2.3、多态基因座百分率(P)为56.3%~68.8%、平均观察杂合度(Ho)为0.072~0.096;而奇异负蝗的相应值依次为A=1.7~2.2,P=43.8~56.3%,Ho=0.070~0.107。从A、P和Ho3个参数可知,短额负蝗遗传多样性明显高于奇异负蝗。6个负蝗种群的平均观察杂合度均明显低于H ardy-W e inberg平衡预期值,表明6个负蝗种群均出现了杂合体缺乏现象。短额负蝗3种群I值为0.971~0.996,奇异负蝗3种群I值为0.982~0.995,短额负蝗与奇异负蝗I值为0.379~0.451,表明种内遗传相似度明显高于种间,从种间I值可知奇异负蝗和短额负蝗属于近缘种。根据R oger’s遗传距离进行的聚类分析表明,两种负蝗可分为两支,且两种负蝗的遗传距离与地理距离均存在明显的相关趋势。两种负蝗的平均FST值都不显著偏离0值(奇异负蝗FST=0.087,p>0.05,短额负蝗FST=0.045,p>0.05),表明该两种负蝗种群间的分化不明显。更多还原

【Abstract】 Ten enzymes（AAT,CK,G3PDH,HEX,IDH,LDH,MDH,ME,PGI,PGM） were examined using horizontal starch gel electrophoresis to estimate the genetic variations in six field populations of two grasshopper species Atractomorpha sinensis and A.peregrina from Shanxi Province,China.The collecting sites were Quwo county,Linfen;Xiangyuan county,Changzhi;Jinyuan district,Taiyuan;Yuanping county,Xinzhou and Fanshi county,Xinzhou.A.sinensis had 43 alleles at 16 loci but A.peregrine had 39 alleles at 15 loci（Idh-1 was deficient）.The zymograms showed that some common alleles were shared at several loci in the two species（Aat-1-b,Aat-2-b,G3pdh-a,Ck-1-b and Ldh-b）.However,Hex-1-a,Hex-2-a,Hex-3-a,Idh-2-b,Mdh-2-b,Mdh-1-f,Pgi-b,Pgm-b were found the common alleles in A.sinensis,and Hex-1-b,Hex-2-b,Hex-3-b,Idh-2-a,Mdh-2-a,Mdh-1-d,Pgi-a,Pgm-c were of high frequency in A.peregrine instead.Most of the observed genotype frequencies significantly deviated from the Hardy-Weinberg expectations in both species.A tendency of clinal distribution of allele frequency was observed at three loci.The frequency of the moderately migrating allele Me-c（0.318～0.740） in A.peregrina,Hex-1-a（0.800～1.000） and Ldh-b（0.487～0.750） in A.sinensis demonstrated increased frequency from north to south.Such tendency suggests that the allele frequency in these three loci may be correlated with the species’ geographic distributions.A.sinensis showed higher genetic diversity than A.peregrina as indicated by the higher mean number of alleles per locus（A=1.9～2.3 in A.sinensis and 1.7～2.2 in A.peregrina）,percentage of polymorphic loci（P=56.3%～68.8% in A.sinensis and 43.8%～56.3% in A.peregrina）,and the observed heterozygosities（H_o=0.072～0.096 in A.sinensis and 0.070～0.107 in A.peregrina）.The observed heterozygosities of the six populations were all noticeably lower than the Hardy-Weinberg expectations,mostly due to heterozygote deficiency for the populations of both species.The overall mean F_ST were small(F_ST=0.045,p>0.05 in A.sinensis populations and 0.087,p>0.05 in A.peregrina populations).Nei’s genetic identity（I） estimates indicate low intraspecific（> 0.95） but higher interspecific（0.377～0.447） genetic diversity.The cluster analysis based on modified Roger’s genetic distance（D） showed that the two species were divided into two branches.Both species were of limited dispersal capacity and a moderate geographical barrier might significantly restrict the gene exchange among populations,which tends to accumulate local genetic differentiations.The A.sinensis populations used in this study were apart from 155.2 to 271.4km and the A.peregrina populations were apart from 78.8 to 174.9km with the observable physical barriers.The allozyme data showed only minimal genetic differentiation at population level,most likely as a result of gene exchange.It is reasoned that natural factors and human agricultural activities might have facilitated migration and dispersal for the two species.更多还原