Genetic diversity in the IIS6 domain of Voltage Gated Sodium Channel (VGSC) gene among Aedes aegypti populations from different geographical regions in India

Abstract

This study provides critical insights into the genetic diversity of the IIS6 domain of the VGSC gene in Aedes aegypti populations across various regions in India, focusing on two mutations: S989P and V1016G. Samples were collected from seven different cities across the country, including Dibrugarh, Kolkata, Berhampur, Bhopal, Bengaluru, Ghaziabad, and Aurangabad. The IIS6 domain was amplified and sequenced, revealing that the V1016G mutation was found at a higher frequency compared to the S989P mutation. The S989P mutation was most prevalent in Berhampur, followed by Bengaluru, while V1016G mutation showed high frequencies in Dibrugarh, followed by Berhampur. Additionally, the study identified intron polymorphisms within the VGSC gene, with the type A intron being relatively rare. However, the type A intron was observed in samples harbouring both mutant and wild alleles for both mutations. The regional variation in the frequencies of these mutations indicates complex evolutionary dynamics potentially influenced by local environmental factors and insecticide application practices. Interestingly, the high frequency of these alleles also correlated with the genetic structure of the mosquito populations, suggesting that gene flow might be playing a role in spreading these mutations. Regular monitoring of these mutations could serve as important indicators in assessing the status of resistance to pyrethroids and guide nationwide mosquito control efforts. This research underscores the necessity for localized vector control strategies and continuous genetic surveillance to manage insecticide resistance effectively.