In notable back-to-back papers appearing in the prestigioous journal Science in October, teams of researchers, one led by Nora Besansky, a professor of biological sciences and a member of the Eck Institute for Global Health at the University of Notre Dame, provided evidence that Anopheles gambiae, which is one of the major mosquito carriers of the malaria parasite in Sub-Saharan Africa, is evolving into two separate species with different traits.
Another significant study appearing in this week's edition of the Proceedings of the National Academy of Sciences (PNAS) and also led by Besansky suggests that the mosquitoes' immune response to malaria parasites, mediated by a gene called "TEP1," is one of the traits that differ between the two forms of Anopheles gambiae.
Both papers have major implications for malaria controls efforts and could eventually lead to new malaria prevention efforts.
The Science papers described a painstaking genomic analysis by Besansky and an international consortium of scientists that revealed that the two varieties of Anopheles gambiae, called M and S, which Besansky describes as physically indistinguishable, are evolving into two distinct species.
In the new PNAS study, the researchers performed genome-wide comparisons of M and S to pinpoint the genetic differences that could help explain how they are adapting to different larval habitats. One of the genomic regions with the most pronounced differences between M and S contained the TEP1 gene.
The researchers report that they found a distinct resistance allele (one of two or more forms of the DNA sequence of a particular gene) of TEP1 circulating only in M mosquitoes despite the fact that M and S mosquitoes live side-by-side in many parts of Africa. The authors demonstrated that this allele confers resistance to human malaria parasites. The patterns of genetic and geographic variation in the TEP1 gene suggest that this resistance allele a
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University of Notre Dame