title: Topi, an IS630/Tc1/mariner-type transposable element in the African malaria mosquito, Anopheles gambiae.
abstract: IS630/Tc1/mariner elements are diverse and widespread within insects. The African malaria mosquito, Anopheles gambiae, contains over 30 families of IS630/Tc1/mariner elements although few have been studied in any detail. To examine the history of Topi elements in An. gambiae populations, Topi elements (n=73) were sampled from five distinct populations of An. gambiae from eastern and western Africa and evaluated with respect to copy number, nucleotide diversity and insertion site-occupancy frequency. Topi 1 and 2 elements were abundant (10-34 per diploid genome) and highly diverse (pi=0.051). Elements from mosquitoes collected in Nigeria were Topi 2 elements and those from mosquitoes collected in Mozambique were Topi 1 elements. Of the 49 Topi transposase open reading frames sequenced none were found to be identical. Intact elements with complete transposase open reading frames were common, although based on insertion site-occupancy frequency data it appeared that genetic drift was the major force acting on these IS630/Tc1/mariner-type elements. Topi 3 elements were not recovered from any of the populations sampled in this study and appear to be rare elements in An. gambiae, possibly due to a recent introduction.
authors.affiliation: Center for Biosystems Research, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA.
authors.forename: Ramanand A
authors.initials: RA
authors.lastname: Subramanian
authors.forename: Olabiyi O
authors.initials: OO
authors.lastname: Akala
authors.forename: Johnson O
authors.initials: JO
authors.lastname: Adejinmi
authors.forename: David A
authors.initials: DA
authors.lastname: O'Brochta
mesh_terms: D000349:Africa; D000818:Animals; D000852:Anopheles / Q000235:genetics*; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D018628:Gene Dosage; D017344:Genes, Insect; D040961:Genetic Drift; D016366:Open Reading Frames; D010802:Phylogeny; D012641:Selection, Genetic
chemical_list: D004251:DNA Transposable Elements