Nayar Jai K, Knight J W, Munstermann L E
Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, 200 9th St., S.E., Vero Beach, FL 32962, USA.
J Med Entomol. 2003 Nov;40(6):882-9. doi: 10.1603/0022-2585-40.6.882.
Culex (Culex) pipiens quinquefasciatus Say field population from Vero Beach, FL, sampled monthly over a period of 8 mo, a colony sample, and six geographic samples were analyzed for genetic variation at 12 enzymes (10 "neutral" gene enzymes with 11 putative loci and two "complex" gene enzymes) by using polyacrylamide gel electrophoresis. The analysis of the 11 putative loci in both temporal and geographic samples showed that the four loci (Gpi, Hk, Mdhp-2, and Pgm) diagnostic of Cx. p. quinquefasciatus in the southern United States are present in similar frequencies in Florida samples. The Cx. p. quinquefasciatus colony sample showed significantly lower genetic variation than the temporal field samples, measured by mean number of alleles per locus (colony 1.2 +/- 0.1 versus field 1.44 +/- 0.03), percentage of polymorphic loci (colony 18.2% versus field 28.4%), mean observed heterozygosity (H(o) = colony 0.027 +/- 0.02 versus field 0.09 +/- 0.01), and mean Hardy-Weinberg expected heterozygosity (H(e) = colony 0.025 +/- 0.02 versus field 0.085 +/- 0.01). Three of the 11 loci (Acoh, Pgd, and Pgm) from the Vero Beach field samples showed bimodal patterns in their frequencies of the most common allele during peak density of the population. The low value of F(st) of 0.058 indicated minimum population substructuring among the temporal samples. Genetic variability values between geographic samples from the Florida panhandle and south Florida were not significant. Gene flow estimates based on F(ST), = 0.05, indicating low levels of gene flow among the geographic samples of Cx. p. quinquefasciatus. The average Nei's and modified Rogers' genetic distances among the six populations were 0.005 +/- 0.001 and 0.077 +/- 0.007, respectively. The cluster analysis did not suggest geographic clustering. The analysis of the "complex" gene enzymes in both temporal and geographic samples of Cx. p. quinquefasciatus from Florida showed the presence of two highly amplified esterases (Estbeta1 and Estalpha2\Estbeta2), indicating resistance to organophosphate insecticides and highly amplified Aldox enzyme (an enzyme that indicates resistance to at least one insecticide and a herbicide). Comparison of our results with previous studies on Cx. p. quinquefasciatus populations in the United States indicates that the genetic characteristics of the Florida populations of Cx. p. quinquefasciatus are very similar to populations from areas where ecological conditions are very different.
对来自佛罗里达州维罗海滩的致倦库蚊（库蚊属）野外种群进行了分析，该种群在8个月的时间里每月采样一次，同时分析了一个群体样本和六个地理样本，通过聚丙烯酰胺凝胶电泳检测12种酶（10种“中性”基因酶，有11个假定基因座，以及2种“复杂”基因酶）的遗传变异情况。对时间样本和地理样本中11个假定基因座的分析表明，在美国南部用于诊断致倦库蚊的四个基因座（磷酸葡萄糖异构酶、己糖激酶、苹果酸脱氢酶-2和磷酸葡萄糖变位酶）在佛罗里达样本中的频率相似。致倦库蚊群体样本的遗传变异明显低于时间野外样本，以每个基因座的平均等位基因数衡量（群体为1.2±0.1，野外为1.44±0.03）、多态性基因座百分比（群体为18.2%，野外为28.4%）、平均观察杂合度（H(o)=群体0.027±0.02，野外0.09±0.01）以及平均哈迪-温伯格期望杂合度（H(e)=群体0.025±0.02，野外0.085±0.01）。来自维罗海滩野外样本的11个基因座中的三个（乙醇脱氢酶、6-磷酸葡萄糖脱氢酶和磷酸葡萄糖变位酶）在种群密度峰值时其最常见等位基因的频率呈现双峰模式。F(st)值为0.058，表明时间样本间的种群亚结构最小。佛罗里达狭长地带和南佛罗里达地理样本之间的遗传变异性值不显著。基于F(ST)=0.05的基因流估计表明，致倦库蚊地理样本间的基因流水平较低。六个种群间的平均内氏遗传距离和修正罗杰斯遗传距离分别为0.005±0.001和0.077±0.007。聚类分析未显示出地理聚类现象。对来自佛罗里达的致倦库蚊时间样本和地理样本中“复杂”基因酶的分析表明，存在两种高度扩增的酯酶（Estbeta1和Estalpha2\Estbeta2），表明对有机磷杀虫剂有抗性，以及高度扩增的醛氧化酶（一种表明对至少一种杀虫剂和一种除草剂有抗性的酶）。将我们的结果与之前对美国致倦库蚊种群的研究进行比较表明，佛罗里达致倦库蚊种群的遗传特征与生态条件差异很大地区的种群非常相似。
