RESUMO
Galaxias maculatus is one of the world's most widely distributed freshwater fish. This species has a marine-tolerant juvenile phase, and a geographical range extending through much of the southern hemisphere. We conducted phylogeographic analyses of 163 control region haplotypes of G. maculatus, including samples from New Zealand (five locations), Tasmania (one location) and Chile (one location). A lack of genetic structure among New Zealand samples suggests that marine dispersal facilitates considerable gene flow on an intra-continental scale. The discovery of a Tasmanian-like haplotype in one of 144 New Zealand samples indicates that inter-continental marine dispersal occurs but is insufficient to prevent mitochondrial DNA differentiation among continents. The sister relationship of Tasmanian and New Zealand clades implies that marine dispersal is an important biogeographical mechanism for this species. However, a vicariant role in the divergence of eastern and western Pacific G. maculatus cannot be rejected.
Assuntos
Peixes/genética , Animais , Sequência de Bases , Chile , Primers do DNA/genética , DNA Mitocondrial/genética , Água Doce , Variação Genética , Genética Populacional , Haplótipos , Nova Zelândia , Filogenia , TasmâniaRESUMO
Twenty-eight populations representing a worldwide distribution of Aedes aegypti were tested for their ability to become orally infected with yellow fever virus (YFV). Populations had been analyzed for genetic variations at 11 isozyme loci and assigned to one of 8 genetic geographic groups of Ae. aegypti. Infection rates suggest that populations showing isozyme genetic relatedness also demonstrate similarity to oral infection rates with YFV. The findings support the hypothesis that genetic variation exists for oral susceptibility to YFV in Ae. aegypti.
Assuntos
Aedes/microbiologia , Insetos Vetores/microbiologia , Vírus da Febre Amarela/crescimento & desenvolvimento , Aedes/enzimologia , Aedes/genética , África , Animais , Ásia , América Central , Feminino , Variação Genética , Isoenzimas/análise , Boca/microbiologia , América do Sul , Estados Unidos , Índias OcidentaisRESUMO
Twenty-eight populations representing a worldwide distribution of Aedes aegypti were tested for their ability to become orally infected with yellow fever virus (YFV). Populations had been analyzed for genetic variations at 11 isozyme loci and assigned to one of 8 genetic geographic groups of Ae. aegypti. Infection rates suggest that populations showing isozyme genetic relatedness also demonstrate similarity to oral infection rates with YFV. The findings support the hypothesis that genetic variation exists for oral susceptibility to YFV in Ae. aegypti.(AU)
Assuntos
Humanos , 21003 , Feminino , Aedes/microbiologia , Insetos Vetores/microbiologia , Vírus da Febre Amarela/crescimento & desenvolvimento , Aedes/enzimologia , África , Ásia , América Central , Estados Unidos , Variação Genética , Índias Ocidentais , Isoenzimas/análise , Boca/microbiologia , América do SulRESUMO
Using starch gel electrophoresis, we have analyzed genetic variation at 11 loci in 18 Caribbean collections of Aedes aegypti. Our results show that, while there is some relationship between geographic proximity and genetic distance, the overall picture among islands is one of gene frequency patchiness , with some collections clearly not conforming to any geographic pattern. We attribute this to the combined effects of high rates of gene flow among islands and with the mainland American continent, and the activities of various vector control agencies in the region.