Single nucleotide polymorphism (SNP) in the doublesex (dsx) gene splice sites and relevance for its alternative splicing in the malaria vector Anopheles gambiae

Abstract

Background: Malaria burden continues to be significant in tropical regions, and conventional vector control methods are faced with challenges such as insecticide resistance. To overcome these challenges, additional vector control interventions are vital and include modern genetic approaches as well as classical methods like the sterile insect technique (SIT). In the major human malaria vector Anopheles gambiae, a candidate gene favourable for sterility induction is the doublesex (dsx) gene, involved in mosquitos’ somatic sexually dimorphic traits determination. However, the pathways that trigger the signal of dsx gene exon skipping alternative splicing mechanism in anopheline mosquitoes are not well characterized. This study aims to screen the An. gambiae dsx gene splice site sequences for single-nucleotide polymorphisms (SNPs) that could be critical to its alternative splicing. Methods: Variant annotation data from Ag1000G project phase 2 was analysed, in order to identify splice-relevant SNPs within acceptor and donor splice sites of the An. gambiae dsx gene (Agdsx). Results: SNPs were found in both donor and acceptor sites of the Agdsx. No splice-relevant SNPs were identified in the female-specific intron 4 acceptor site and the corresponding region in males. Two SNPs (rs48712947, rs48712962) were found in the female-specific donor site of exon 5. They were not specific to either males or females as the rs48712947 was found in female mosquitoes from Cameroon, and in both males and females from Burkina Faso. In the other splice sites, the intron 3 acceptor site carried the greatest abundance of SNPs.   Conclusions: There were no gender association between the identified SNPs and the random distribution of these SNPs in mosquito populations. The SNPs in Agdsx splice sites are not critical for the alternative splicing. Other molecular mechanisms should be considered and investigated.