From a medical perspective, the Anopheles gambiae complex is arguably the most important group of insects; it is the primary vector of malaria in Africa, and hence the world. The goal of these projects is to understand the evolutionary genetics of the group; this includes understanding the genetic basis of sterility barriers between species and the dynamics of gene exchange between species. Previous research has indicated that two closely related species may be exchanging genetic material by hybridizing in nature, the phenomenon known as introgression. But it appears that not all parts of a species genome are equally able to cross species boundaries. Using genetic markers (microsatellites) we intend to directly test which parts of the genome are responsible for sterility barriers. This will be done by making interspecific crosses, backcrossing fertile hybrid females to males of each species, assessing the reproductive status of the backcross progeny, and genotyping them for at least 24 microsatellites spread evenly across the genome. When regions responsible for sterility are identified, finer scale mapping will be done by increasing the density of microsatellite markers. In a related study, we will determine which parts of the genome are able to persist in freely breeding backcross populations for up to twenty generations. The second project concerns the dynamics of introgression. In particular, the question of whether the introgression is an ancient phenomenon or a recent, ongoing process will be addressed. This project will involve examination of DNA sequences in a chromosome inversion, the """"""""a"""""""" inversion of the left arm of the second chromosome (2La), for which there is good evidence of interspecies transfer. The history of this inversion will be determined using phylogenetic procedures and statistical analysis for the number on introgression events most consistent with the data. Understanding whether the two most important vectors of malaria in the world (An. gambiae and An. arabiensis) are exchanging genes is vitally important to control measures aimed at these species.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
3R01AI046018-01A1S1
Application #
6321270
Study Section
Special Emphasis Panel (ZRG1 (01))
Program Officer
Aultman, Kathryn S
Project Start
2000-04-01
Project End
2004-03-31
Budget Start
2000-06-01
Budget End
2001-03-31
Support Year
1
Fiscal Year
2000
Total Cost
$12,568
Indirect Cost
Name
Yale University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
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Schielke, Erika; Costantini, Carlo; Carchini, Gianmaria et al. (2007) Development of a molecular assay to detect predation on Anopheles gambiae complex larval stages. Am J Trop Med Hyg 77:464-6

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