DNA barcoding and molecular evolution of mosquito vectors of medical and veterinary importance

Abstract

Mosquitoes (Diptera: Culicidae) are a key threat for millions of people worldwide, since they act as vectors for devastating pathogens and parasites. The standard method of utilisation of morphological characters becomes challenging due to various factors such as phenotypical variations. We explored the complementary approach of CO1 gene-based identification, analysing ten species of mosquito vectors belonging to three genera, Aedes, Culex and Anopheles from India. Analysed nucleotide sequences were found without pseudo genes and indels; they match with high similarity in nucleotide Basic Local Alignment Search Tool (BLASTn) search. The partial CO1 sequence of Anopheles niligricus was the first time record submitted to National Center for Biotechnology Information (NCBI). Mean intra- and interspecies divergence was found to be 1.30 and 3.83 %, respectively. The congeneric divergence was three times higher than the conspecifics. Deep intraspecific divergence was noted in three of the species, and the reason could be explained more accurately in the future by improving the sample size across different locations. The transitional and transversional substitutions were tested individually. Ts and Tv substitutions in all the 1st, 2nd and 3rd codons were estimated to be (0.44, 99.51), (40.35, 59.66) and (59.16, 40.84), respectively. Saturation of the sequences was resolved, since both the Ts and Tv exhibited a linear relationship suggesting that the sequences were not saturated. NJ and ML tree analysis showed that the individuals of the same species clustered together based on the CO1 sequence similarity, regardless of their collection site and geographic location. Overall, this study adds basic knowledge to molecular evolution of mosquito vectors of medical and veterinary importance and may be useful to improve biotechnological tools employed in Culicidae control programmes.

Molecular characterization of Anopheline (Diptera: Culicidae) mosquitoes from eight geographical locations of Sri Lanka

“…annularis specimens from Sri Lanka, further confirming the sibling status of An. annularis in Sri Lanka [4]. Moreover, An.…”

“…The two study sites are located in two climatic zones and the Wariyapola site is at a higher elevation (low-country intermediate zone) than the Tirunelveli site (dry zone) (≈80 m difference). A study in India has observed very high intra-specific divergence of 4.9% among Anopheles stephensi samples and variation in the climate of the areas was found as the main reason for this high intra-specific divergence [4]. Further, Murugan et al [4] suggest increasing the sample size and expanding the geographical area of collection to clarify this answer.…”

“…A study in India has observed very high intra-specific divergence of 4.9% among Anopheles stephensi samples and variation in the climate of the areas was found as the main reason for this high intra-specific divergence [4]. Further, Murugan et al [4] suggest increasing the sample size and expanding the geographical area of collection to clarify this answer. Anopheles varuna was collected only from two study sites located at different elevations and climatic zones and sequences obtained from a relatively small sample would have been the reason behind this high intra-specific divergence, which needs further investigation.…”

Evaluating the accuracy of morphological identification of insect pests of rice crops using DNA barcoding

“…juveniles, early instar and pupae are not identified by routine taxonomy as most of the morphotaxonomic keys are used for the analysis of adults only (Barrett & Hebert 2005). Phenotypic plasticity often complicates the morphological identifications (Murugan et al 2016). Cryptic species are also difficult to identify on the basis of morphology.…”

The human immune system’s response to carcinogenic and other infectious agents transmitted by mosquito vectors

“…A comprehensive list of the main pathogens and parasites associated with mosquito vectors is available (see Murugan et al 2016). There are many less well known pathogens carried by mosquitoes, for example 83 bacterial species belonging to 31 bacterial genera in the midgut of Culex quinquefasciatus mosquitoes (Chandel et al 2013).…”