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Updated: Jul 31, 2026
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A Multi-detection Assay for Malaria Transmitting Mosquitoes
Published on: February 28, 2015
Centromere-proximal differentiation and speciation in Anopheles gambiae
Aram D Stump1, Meagan C Fitzpatrick, Neil F Lobo
1Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA.
Summary
The M and S forms of Anopheles gambiae mosquito are diverging due to natural selection at the X chromosome
Area of Science:
- Genetics
- Evolutionary Biology
- Entomology
Background:
- The M and S molecular forms of Anopheles gambiae are implicated in malaria transmission.
- These mosquito forms are undergoing speciation, adapting to diverse environments.
- Gene flow between these forms complicates understanding their divergence.
Purpose of the Study:
- To investigate the role of reduced recombination at the centromeric end of the X chromosome in facilitating Anopheles gambiae speciation.
- To test the hypothesis that divergent natural selection counters gene flow at the proximal X chromosome.
Main Methods:
- Sequencing of introns from 22 X chromosome genes in M and S forms from West Africa.
- Analysis of nucleotide diversity and genetic differentiation along the X chromosome.
- Comparative analysis with the sibling species Anopheles arabiensis.
Main Results:
- Nucleotide diversity was high distally and low proximally on the X chromosome in both M and S forms.
- Genetic differentiation between M and S forms was low distally and high proximally.
- High divergence was observed between Anopheles gambiae and Anopheles arabiensis across the X chromosome.
Conclusions:
- The observed pattern suggests divergent natural selection acting on the proximal X chromosome, counteracting gene flow.
- Reduced genetic recombination in this region likely facilitates speciation in Anopheles gambiae.
- Selection appears to have occurred before the current geographic expansion of these mosquito forms.
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