The Anopheles gambiae 2La chromosome inversion is associated with susceptibility to Plasmodium falciparum in Africa.

Michelle M Riehle,Boubacar Coulibaly,Awa Gneme,Abdrahamane Fofana,N’Fale Sagnon,Adrien Pain,Kenneth D Vernick,Sekou F Traore,Wamdaogo M Guelbeogo,Abdoul H Beavogui,Francois Renaud,Tullu Bukhari,Emmanuel Bischoff

doi:10.7554/elife.25813

Abstract

Chromosome inversions suppress genetic recombination and establish co-adapted gene complexes, or supergenes. The 2La inversion is a widespread polymorphism in the Anopheles gambiae species complex, the major African mosquito vectors of human malaria. Here we show that alleles of the 2La inversion are associated with natural malaria infection levels in wild-captured vectors from West and East Africa. Mosquitoes carrying the more-susceptible allele (2L+a) are also behaviorally less likely to be found inside houses. Vector control tools that target indoor-resting mosquitoes, such as bednets and insecticides, are currently the cornerstone of malaria control in Africa. Populations with high levels of the 2L+a allele may form reservoirs of persistent outdoor malaria transmission requiring novel measures for surveillance and control. The 2La inversion is a major and previously unappreciated component of the natural malaria transmission system in Africa, influencing both malaria susceptibility and vector behavior.

Highlights

Mosquitoes of the Anopheles gambiae species complex are primary African vectors of the human malaria parasite, Plasmodium falciparum, which is responsible for extensive human morbidity and mortality
The 2La inversion is significantly associated with differential malaria infection
Infection rates of P. falciparum were measured in mosquitoes of the A. gambiae species complex in the Western Highlands of Kenya, in the forested zone of southern Republic of Guinea (Guinea-Conakry), and in the Sudan-Savanna zone of Burkina Faso (Figure 1)

Summary

Introduction

Mosquitoes of the Anopheles gambiae species complex are primary African vectors of the human malaria parasite, Plasmodium falciparum, which is responsible for extensive human morbidity and mortality. At least part of the widespread geographic success of A. gambiae and its sister taxon A. coluzzii (previously called the A. gambiae S and M molecular forms, respectively [Coetzee et al, 2013]) can be attributed to segregating paracentric chromosomal inversions. Inversions are physical rearrangements of a chromosome segment that suppress recombination and limit exchange of variation between two alternate suites of alleles.

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Conclusion