Compensatory Base Changes Reveal Sexual Incompatibility among Members of the Anopheles subpictus Sensu Lato (Diptera: Culicidae) Species Complex in Sri Lanka.

D P W Jayatunga,B G D N K De Silva,I N Harischandra,N V Chandrasekharan

doi:10.3390/life11030211

D P W Jayatunga, B G D N K De Silva + Show 2 more

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https://doi.org/10.3390/life11030211

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Abstract

The mosquito Anopheles (Cellia) subpictus sensu lato (s.l.) is a major secondary vector of malaria in Sri Lanka. The sibling species composition in this species complex in Sri Lanka remains debatable. Compensatory base changes (CBCs) in the secondary structures of internal transcribed spacer 2 (ITS2) are reliable sources to predict sexual incompatibility among closely related species. The objective of the present study was to investigate the An. subpictus s.l. populations in Sri Lanka using the CBC analysis. Mosquito DNA was amplified and sequenced for the ITS2 region. The sequences were annotated using ITS2 Database. ITS2 secondary structures were constructed and analyzed for CBCs using various bioinformatics tools. The ITS2 regions consisted of two different lengths, 575 bp and 480 bp. The two CBCs and three hemi CBCs identified in the present study suggest that there may be at least two sexually incompatible sibling species. In conclusion, it is likely that there may be only two reproductively isolated sibling species in the An. subpictus species complex in Sri Lanka. However, due to high divergence of ITS2 in these species, it is reasonable to assume that they may be undergoing a speciation event to separate as a distinct species.

Highlights

Malaria is a fatal, historical disease in Sri Lanka that is caused by protozoan parasites from the genus Plasmodium
The sequences represented by KP165072 showed a high genetic distance value (K2P = 0.1) with respect to the internal transcribed spacer 2 (ITS2) sequences represented by KP165073-KP165079 (Table 2)
Precise identification of sibling species in An. subpictus species complex plays a pivotal role in malaria elimination due to distinct variations in the biological characteristics such as vector competence [9]

Summary

Introduction

Historical disease in Sri Lanka that is caused by protozoan parasites from the genus Plasmodium. Having a long-documented history of malaria, the country experienced the most devastating epidemics in the period of 1934–1935 [1]. Malaria in Sri. Lanka is highly unstable, such that it has historically fluctuated greatly over the years with significant seasonal differences. The risk of disease recurrence on the island does not fade for being a tourist destination for travelers from malaria-endemic countries across the globe [3]. The presence of malaria vector mosquitoes throughout the island may be responsible for the potential re-emergence of the disease in all parts of the country [4]

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