Koosha Mona, Oshaghi Mohammad Ali, Sedaghat Mohammad Mehdi, Vatandoost Hassan, Azari-Hamidian Shahyad, Abai Mohammad Reza, Hanafi-Bojd Ahmad Ali, Mohtarami Fatemeh
Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, P.O.Box 14155-6446, Tehran, Iran.
Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, P.O.Box 14155-6446, Tehran, Iran.
Exp Parasitol. 2017 Oct;181:102-110. doi: 10.1016/j.exppara.2017.08.003. Epub 2017 Aug 14.
Members of the Culex (Culex) pipiens assemblage are known vectors of deadly encephalitides, periodic filariasis, and West Nile virus throughout the world. However, members of this assemblage are morphologically indistinguishable or hard to distinguish and play distinct roles in transmission of the diseases. The current study aimed to provide further evidence on utility of the two most popular nuclear (ITS2-rDNA) and mitochondrial (COI barcode region) genetic markers to identify members of the assemblage. Culex pipiens assemblage specimens from different climate zones of Iran were collected and identified to species level based on morphological characteristics. Nucleotide sequences of the loci for the specimens plus available data in the GenBank were analyzed to find species specific genetic structures useful for diagnosis purposes. ITS2 region was highly divergent within species or populations suggesting lack of consistency as a reliable molecular marker. In contrast, sequence analysis of 710 bp of COI gene revealed three fixed haplotypes named here "C, T, H" within the assemblage which can be distinguished by HaeIII and AluI enzymes. There were a correlation between the haplotypes and the world climate regions, where the haplotypes H/T and C are present mainly in temperate and tropical regions of the world, respectively. In the New world, Australia, and Japan only haplotype H is found. In conjunction between tropical and temperate regions such Iran, China, and Turkey, a mix of C/H or C/H/T are present. Although, the haplotypes are not strictly species-specific, however, Cx. quinquefasciatus was mainly of haplotype C. Due to the lack of mating barrier and questionable taxonomic situation of the complex members, the mentioned haplotypes in combination with other morphological and molecular characters might be used to address the genetic structure of the studied populations.
致倦库蚊复合组的成员是全球致命性脑炎、周期性丝虫病和西尼罗河病毒的已知传播媒介。然而，该复合组的成员在形态上难以区分或很难区分，并且在疾病传播中发挥着不同的作用。当前的研究旨在为两种最常用的核基因（ITS2-rDNA）和线粒体基因（COI条形码区域）遗传标记在鉴定该复合组成员方面的实用性提供进一步证据。收集了来自伊朗不同气候区的致倦库蚊复合组标本，并根据形态特征将其鉴定到物种水平。分析了这些标本位点的核苷酸序列以及GenBank中的可用数据，以找到可用于诊断目的的物种特异性遗传结构。ITS2区域在物种或种群内高度分化，这表明其作为可靠分子标记缺乏一致性。相比之下，对710 bp的COI基因进行序列分析后发现，该复合组内有三种固定的单倍型，在此命名为“C、T、H”，它们可以通过HaeIII和AluI酶区分开来。单倍型与世界气候区域之间存在相关性，其中单倍型H/T和C分别主要存在于世界的温带和热带地区。在新世界、澳大利亚和日本仅发现单倍型H。在热带和温带地区交界处，如伊朗、中国和土耳其，则存在C/H或C/H/T的混合情况。虽然单倍型并非严格物种特异性，但致倦库蚊主要为单倍型C。由于该复合组成员缺乏交配屏障且分类情况存在疑问，上述单倍型结合其他形态和分子特征可能有助于研究种群的遗传结构。
