Radiation with reticulation marks the origin of a major malaria vector

Area of Science:

• Evolutionary biology
• Genomics
• Medical entomology

Background:

• Introgression, or gene flow between species, is increasingly recognized but its evolutionary impact remains unclear.
• The Anopheles funestus complex (AFC) is a group of malaria vectors crucial for public health, yet its evolutionary history and diversification are understudied.
• Most Anopheles mosquitoes, including major malaria vectors, evolved from radiations of non-vector species, suggesting adaptation via genetic exchange.

Purpose of the Study:

• To investigate the role of introgression in the diversification of the Afrotropical Anopheles funestus complex (AFC).
• To explore the potential link between introgression and the enhanced vectorial capacity of Anopheles funestus.
• To understand the evolutionary history and species relationships within the AFC.

Main Methods:

• De novo genome assembly and whole-genome resequencing of AFC species.
• Phylogenomic and population genomic analyses to reconstruct species relationships and gene flow.
• Investigating patterns of interspecific gene flow and introgression events.

Main Results:

• Extensive interspecific gene flow has significantly shaped the evolutionary history of the AFC.
• A major, asymmetrical introgression event occurred from a distinct AFC lineage into Anopheles funestus.
• This introgression predated and likely facilitated the wide geographic expansion of Anopheles funestus across Africa.

Conclusions:

• Introgression plays a significant role in the diversification of the Anopheles funestus complex.
• Gene flow may be a key mechanism enabling adaptation to new environments and enhancing vector competence in Anopheles mosquitoes.
• Understanding introgression in vector populations is critical for malaria control strategies.