Anopheles gambiae cytogenetics

Dynamic spatial and temporal considerations in reproductive isolation of molecular and chromosomal forms of Anopheles gambiae in Africa. (Post Doctoral T32 NIH funding)

Years of research in Africa done by Lanzaro and I confirm our view that gene flow between Anopheles gambiae molecular forms known as Savanna and Forest M and S forms is not consistent in both time and space which makes distinguishing and naming these forms a dynamic challenge. Assymetric introgression (Marsden et al.2011) and presence of islands of introgression within the genome, which themselves are not consistent makes this topic of incipient speciation such a difficult but nevertheless intellectually highly stimulating one. There is definitely some degree of reproductive isolation between the forms which have allowed for “somewhat” reliable PCR identification tools to be developed and differences found (for example in wing morphology- Sanford et al. 2010). Studies are currently ongoing by Yoosook Lee (Adjuct faculty- Department of PMI, Vet Med at UC Davis) and postdocs, Clare Marsden, Michelle Sanford and Laura Norris to investigate introgression and to identify what factors (likely environmental) that affect this introgression.

 One cannot ignore investigating the dynamic nature of An. gambiae chromosomal forms which also change in both time and space acrossAfrica. Much still needs to be learnt about the role and environmental fitness advantageous of maintaining such high chromosomal polymorphisms in these mosquitoes. While there is no specific funding for this project it is an area of research we hope to expand on.  

 Slotman, M. A., Tripet, F., Cornel, A. J., Meneses, C. R., Lee, Y., Reimer, L. J., Thieman, L. J., Fondjo, E., Fofana, A., Traore, S. F. and Lanzaro, G. C. Evidence for subdivision within the M molecular form of Anopheles gambiae. Mol. Ecology 16:639-649. 2007.

 Lee, Y., Cornel, A. J., Meneses, C., Fofana, A., Andrianarivo, A. G., McAbee, R. D., Fondjo, E., Traoré S. F., and Lanzaro, G. C. Ecological and genetic relationships of the Forest-M form among chromosomal and molecular forms of the malaria vector Anopheles gambiae sensu stricto. Malaria Journal 8: 75 doi:10.1186/1475-2875-8-75 2009.  Received 2009 open data award by Biomed Central Publishers.

 Marsden, C. D., Lee, Y., Nieman, C., Sanford, M., Dinis, J., Marins, C., Rodrigues, A., Cornel, A.J., Lanzaro, G. C. Asymmetric introgression between the M and S molecular forms of the malaria vector, Anopheles gambiae, maintains divergence despite extensive hybridisation. Mol. Ecol. 20: 4983-4994. doi:10.1111/j1365X.2011.05339.x. 2011.

 Sanford, M., Demirci, B., Marsden, C.D., Lee, Y., Cornel, A. J., Lanzaro, G. C. Morphological differentiation may mediate mate-choice between incipient species of Anopheles gambiae s.s. PloS One 6(11) e27920. 2011.