Anopheles gambiae
Mosquito
Anopheles gambiae Credit: Photo Courtesy of Jim Gathany, CDC Photoservices
Habitat
The mosquito Anopheles gambiae occurs throughout continental Africa south of the Sahara, as well as its offshore islands. Due to its strong association with humans at all life stages, this mosquito is responsible for transmitting most cases of malignant (Plasmodium falciparum) malaria, from which as many as 2 million children die each year. Breeding sites utilized by A. gambiae are anthropogenic (derived from human activity) in origin. Traditionally these are rain-dependent, temporary pools without vegetation and exposed to full sunlight. Examples abound in and around rural and peri-urban human settlements, including rain-filled tire tracks, hoof prints of domestic animals, and borrow pits excavated for brick-making. Adult females emerging from such sites enter human houses for shelter and blood meals.
Biology
Research in the past decade has revealed two races of A. gambiae that are capable of interbreeding but do so only rarely. Both are equally efficient vectors of malaria, but the races differ in their geographic distribution, ecology, and genetics. One race, referred to as the S molecular form, occurs across Africa and actively breeds in the rainy season, matching the classical description just presented. This form is being sequenced at The Institute for Genomic Research (TIGR). The second race, referred to as the M molecular form and the one being sequenced at The Genome Institute, has only been found in West and Central Africa. This form is associated with irrigated agricultural sites, especially areas where rice is extensively cultivated. Because it has adapted to these non-traditional sites that are available even during the dry season, and because it apparently shows a higher tolerance for aridity in the adult stage, this form is reproductively active in places and times of the year that preclude the S form. As a result of the diversification of A. gambiae, human malaria transmission has been extended spatially and temporally. The very close evolutionary relationship between the races affords the opportunity to genetically dissect the innovations underlying ecological and behavioral differences, opening a window to the speciation process and hopefully offering new targets for vector control.
--Courtesy of Nora Besansky
Sequencing Plan
The National Human Genome Research Institute (NHGRI) of the National Institutes of Health (NIH) is funding the sequencing of the genomes of two strains of the malarial disease vector, Anopheles gambiae, M and S. The original strain sequenced, PEST, was found be of mixed ancestry, now is thought to be a derivation of a cross between M and S. In an attempt to clarify this situation, the J Craig Venter Institute (JCVI) is sequencing the S genome, and the Washington University School of Medicine Genome Institute is sequencing the M genome.
For the M genome, a 5.5X draft assembly, consisting primarily of plasmid end reads and 0.3X fosmid end reads for scaffolding will be performed. An assembly will be produced using a modified version of the PCAP assembler called pcap.rep.poly, which has been designed to improve assembly by merging more highly polymorphic regions. All trace files are available from the NCBI Trace Archive and the WGS data generated is available from The Genome Institute ftp site. The National Human Genome Research Institute (NHGRI), National Institutes of Health (NIH) is providing funding for the sequence characterization of the Anopheles gambiae M genome.
Contacts
| Name | Affiliation |
|---|---|
| Patrick Minx | The Genome Institute, Washington University School of Medicine |
| Nora Besansky | Center for Global Health and Infectious Diseases, University of Notre Dame |
Sequences & Maps
Assemblies
| Name | Date | Description | Blast DBs |
| Anopheles_gambiae_M-3.0 | Oct 08, 2007 | 5.6X | contigs supercontigs |
| Anopheles_gambiae_S-4.2 | Sep 30, 2007 | 5.7X | contigs supercontigs |
Related Links
Others
