The research team of researchers from the University Of Notre Dame, the J.C. Venter Institute, Washington University and the Broad Institute are reporting that two strains of mosquitoes responsible for malaria in Africa are evolving at an unexpected rate into genetically distinct species. This is not good news as it will further complicate the tedious fight against malaria by creating a situation where strategies and medicines developed against malaria may not be effective against both strains
The studies were reported in the magazine Science. The two issues (Science 22 October 2010:Vol. 330. no. 6003, pp. 512 – 514; Science 4 October 2002:Vol. 298. no. 5591, pp. 115 – 117) suggest that the evolution process is occurring faster than previously thought, and point to already substantial differences in the two strains. The two species already able to exploit different habitats.
Malaria kills one child every 30 seconds worldwide, according to World Health Organization. The incidence could be higher in sub-Saharan African.
The work focused on the Anopheles gambiae, the mosquito that is the most transmitter of malaria in sub-Saharan Africa. The study describes the two strains as “M” and “S” strains of the “Anopheles gambiae mosquito
What they found was that the mosquitoes are diverging into two different incipient species, which are called M and S forms. Physically, the two forms are cannot be distinguished, they are and able to interbreed, but their DNAs are diverging into different directions. Their behaviors are different under different conditions.
The ‘M’ form is usually found in around permanent bodies of water and spends most of its life in water environment. This means that it can thrive in dry areas that are normally not good habitats for malaria transmitting mosquitoes.
The S form is used to small, short-lived water bodies and breeds well during the rainy season. It is clear how these ‘tricks’ by the mosquito could undermine current efforts to combat the disease.
Work is ongoing to sequence the genome of the two forms of mosquitoes which could help us to decipher why they are different and how to devise ways to combat them more effectively.
