Pinto J, Lynd A, Elissa N, Donnelly M J, Costa C, Gentile G, Caccone A, do Rosário V E
Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal.
Med Vet Entomol. 2006 Mar;20(1):27-32. doi: 10.1111/j.1365-2915.2006.00611.x.
Point mutations in the voltage-gated sodium channel gene involved in knockdown resistance to DDT and pyrethroid insecticides have been described in several insect species. In the malaria vector Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) two mutations have been identified. The first, consisting of a leucine-phenylalanine substitution at amino acid position 1014, is widespread in West Africa. The second, a leucine-serine substitution at the same position, has to date only been detected in western Kenya. Analysis of the kdr polymorphism in a sample of 106 An. gambiae s.s. of the rDNA S-form/Type I collected in Libreville (Gabon) surprisingly revealed the presence of both East and West African kdr mutations with frequencies of 63% and 37%, respectively. No wild-type alleles were detected and there was an excess of heterozygous genotypes (P = 0.04). In addition, an inconsistency was found during the kdr genotyping procedures by polymerase chain reaction, which could have lead to an underestimation of resistance alleles. The implications of these findings are discussed.
在几种昆虫物种中，已经发现了与滴滴涕和拟除虫菊酯类杀虫剂击倒抗性相关的电压门控钠通道基因点突变。在疟疾媒介冈比亚按蚊（双翅目：蚊科）中，已鉴定出两种突变。第一种突变是在氨基酸位置1014处由亮氨酸替换为苯丙氨酸，在西非广泛存在。第二种突变是在同一位置由亮氨酸替换为丝氨酸，迄今为止仅在肯尼亚西部检测到。对在利伯维尔（加蓬）采集的106只核糖体DNA S型/ I型冈比亚按蚊样本中的击倒抗性（kdr）多态性进行分析，结果令人惊讶地发现，东非和西非的kdr突变均有出现频率分别为63%和37%。未检测到野生型等位基因，并且杂合基因型过量（P = 0.04）。此外，在通过聚合酶链反应进行kdr基因分型的过程中发现了不一致情况，这可能导致抗性等位基因被低估。本文讨论了这些发现的意义。
