Yan G, Chadee D D, Severson D W
Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison 53706, USA.
Genetics. 1998 Feb;148(2):793-800. doi: 10.1093/genetics/148.2.793.
Information on genetic variation within and between populations is critical for understanding the evolutionary history of mosquito populations and disease epidemiology. Previous studies with Drosophila suggest that genetic variation of selectively neutral loci in a large fraction of genome may be constrained by fixation of advantageous mutations associated with hitchhiking effect. This study examined restriction fragment length polymorphisms of four natural Aedes aegypti mosquito populations from Trinidad and Tobago, at 16 loci. These populations have been subjected to organophosphate (OP) insecticide treatments for more than two decades, while dichlor-diphenyltrichlor (DDT) was the insecticide of choice prior to this period. We predicted that genes closely linked to the OP target loci would exhibit reduced genetic variation as a result of the hitchhiking effect associated with intensive OP insecticide selection. We also predicted that genetic variability of the genes conferring resistance to DDT and loci near the target site would be similar to other unlinked loci. As predicted, reduced genetic variation was found for loci in the general chromosomal region of a putative OP target site, and these loci generally exhibited larger F(ST) values than other random loci. In contrast, the gene conferring resistance to DDT and its linked loci show polymorphisms and genetic differentiation similar to other random loci. The reduced genetic variability and apparent gene deletion in some regions of chromosome 1 likely reflect the hitchhiking effect associated with OP insecticide selection.
种群内部和种群之间的遗传变异信息对于理解蚊子种群的进化历史和疾病流行病学至关重要。先前对果蝇的研究表明，基因组中很大一部分选择性中性位点的遗传变异可能受到与搭便车效应相关的有利突变固定的限制。本研究检测了来自特立尼达和多巴哥的四个埃及伊蚊自然种群在16个位点的限制性片段长度多态性。这些种群已经接受有机磷（OP）杀虫剂处理超过二十年，而在此之前滴滴涕是首选杀虫剂。我们预测，与OP靶位点紧密连锁的基因由于与密集OP杀虫剂选择相关的搭便车效应，其遗传变异会减少。我们还预测，赋予对滴滴涕抗性的基因以及靶位点附近的位点的遗传变异性将与其他不连锁位点相似。正如预测的那样，在假定的OP靶位点的一般染色体区域中的位点发现了遗传变异减少，并且这些位点通常比其他随机位点表现出更大的F(ST)值。相比之下，赋予对滴滴涕抗性的基因及其连锁位点显示出与其他随机位点相似的多态性和遗传分化。1号染色体某些区域遗传变异性的降低和明显的基因缺失可能反映了与OP杀虫剂选择相关的搭便车效应。
