Scarpassa V M, Tadei W P, Suarez M F
Coordenação de Pesquisas em Ciências da Saúde, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.
Am J Trop Med Hyg. 1999 Jun;60(6):1010-8. doi: 10.4269/ajtmh.1999.60.1010.
Anopheles nuneztovari is considered an important vector of human malaria in several localities in Venezuela and Colombia. Its status as a vector of human malaria is still unresolved in areas of the Brazilian Amazon, in spite of have been found infected with Plasmodium sp.. For a better understanding of the genetic differentiation of populations of A. nuneztovari, electrophoretic analysis using 11 enzymes was performed on four populations from Brazil and two from Colombia. The results showed a strong differentiation for two loci: alpha-glycerophosphate dehydrogenase (alpha-Gpd) and malate dehydrogenase (Mdh) from 16 loci analyzed. Diagnostic loci were not detected. The populations of A. nuneztovari from the Brazilian Amazon showed little genetic structure and low geographic differentiation, based on the F(IS) (0.029), F(ST) (0.070), and genetic distance (0.001-0.032) values. The results of the isozyme analysis do not coincide with the indication of two lineages in the Amazon Basin by analysis of mitochondrial DNA, suggesting that this evolutionary event is recent. The mean F(ST) value (0.324) suggests that there is considerable genetic divergence among populations from the Brazilian Amazon and Colombia. The genetic distance among populations from the Brazilian Amazon and Colombia is ranges from 0.047 to 0.148, with the highest values between the Brazilian Amazon and Sitronela (SIT) (0.125-0.148). These results are consistent with those observed among members of anopheline species complexes. It is suggested that geographic isolation has reduced the gene flow, resulting in the genetic divergence of the SIT population. Dendrogram analysis showed three large groups: one Amazonian and two Colombia, indicating some genetic structuring. The present study is important because it attempted to clarify the taxonomic status of A. nuneztovari and provide a better understanding of the role of this mosquito in transmission of human malaria in northern South America.
努内斯按蚊被认为是委内瑞拉和哥伦比亚多个地区人类疟疾的重要传播媒介。尽管在巴西亚马逊地区已发现其感染疟原虫，但在该地区其作为人类疟疾传播媒介的地位仍未明确。为了更好地了解努内斯按蚊种群的遗传分化情况，对来自巴西的四个种群和来自哥伦比亚的两个种群进行了使用11种酶的电泳分析。结果显示，在所分析的16个基因座中，有两个基因座存在强烈分化：α-甘油磷酸脱氢酶（α-Gpd）和苹果酸脱氢酶（Mdh）。未检测到诊断性基因座。基于F(IS)（0.029）、F(ST)（0.070）和遗传距离（0.001 - 0.032）值，巴西亚马逊地区的努内斯按蚊种群显示出较小的遗传结构和较低的地理分化。同工酶分析结果与线粒体DNA分析表明的亚马逊流域两个谱系不一致，这表明这一进化事件是近期发生的。平均F(ST)值（0.324）表明，巴西亚马逊地区和哥伦比亚的种群之间存在相当大的遗传差异。巴西亚马逊地区和哥伦比亚种群之间的遗传距离在0.047至0.148之间，其中巴西亚马逊地区与西特罗内拉（SIT）之间的值最高（0.125 - 0.148）。这些结果与按蚊物种复合体成员中观察到的结果一致。有人认为地理隔离减少了基因流动，导致了SIT种群的遗传分化。聚类分析显示出三大组：一组是亚马逊地区的，两组是哥伦比亚的，这表明存在一定的遗传结构。本研究很重要，因为它试图阐明努内斯按蚊的分类地位，并更好地了解这种蚊子在南美洲北部人类疟疾传播中的作用。
