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1.
Med Vet Entomol ; 30(2): 235-40, 2016 06.
Article in English | MEDLINE | ID: mdl-26744174

ABSTRACT

The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success.


Subject(s)
Aedes/genetics , Genetic Variation , Insect Vectors/genetics , Aedes/physiology , Africa South of the Sahara , Animals , Brazil , Insect Vectors/physiology , Mexico , Population Dynamics , Puerto Rico , Queensland , Seasons , United States
2.
J Med Entomol ; 38(5): 675-83, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11580040

ABSTRACT

The phylogenetic relationships among 18 species of Triatominae were inferred based on mitochondrial DNA (mtDNA) sequences. The species of Triatoma included 11 belonging to the infestans complex [T. infestans (Klug), T. guasayana Wygodzinsky & Abalos, T. sordida (Stål), T. platensis Neiva, T. brasiliensis Neiva, T. rubrovaria (Blanchard), T. vitticeps (Stål), T. delpontei Romaña & Abalos, T. maculata (Erichson), T. patagonica Del Ponte, and T. matogrossensis Leite & Barbosa] and four others of the same genus but of different complexes [T. circummaculata (Stål), T. protracta (Uhler), T. dimidiata (Latreille), and T. mazzottii Usinger]. As possible outgroups we used Mepraia spinolai Mazza, Panstrongylus megistus (Burmeister), and Rhodnius prolixus Stål. We analyzed mtDNA fragments of the 12S and 16S ribosomal RNA genes from each of the 18 species, as well as of the cytochrome oxidase I (COI) gene from nine. The 12S, 16S, and COI gene sequences were analyzed individually and combined. All of the phylogenetic analyses unambiguously supported two clusters: one including T. infestans, T. platensis, and T. delpontei, and the other T. sordida and T. mutagrossensis. Inclusion of T. circummaculata into the infestans complex was confirmed, although this is in disagreement with the morphological classification. On the other hand, our analyses showed that T. dimidiata is closely related to a phylosoma complex species, T. mazzottii. This is consistent with the tentative classification previously made based on morphological characters. The issue of the monophyly of the genus Triatoma remains unresolved.


Subject(s)
DNA, Mitochondrial/analysis , Triatoma/genetics , Animals , Base Composition , Base Sequence , Genes, Insect , Genetic Variation , Molecular Sequence Data , Phylogeny , RNA, Ribosomal/analysis , RNA, Ribosomal, 16S/analysis , Sequence Analysis, DNA , Triatoma/classification , Triatominae/classification , Triatominae/genetics
3.
J Med Entomol ; 35(3): 232-8, 1998 May.
Article in English | MEDLINE | ID: mdl-9615540

ABSTRACT

DNA sequence comparisons of 12S, 16S, and COI mitochondrial DNA (mtDNA) genes were used to infer phylogenetic relationships among 8 species of Triatoma [7 belonging to the infestans complex and T. circummaculata (Stål), a member of a different complex based on morphology]. There was remarkable mtDNA similarity between T. infestans (Klug) and T. platensis Neiva that can be explained by mtDNA introgression. Evolutionary trees were constructed using Panstrongylus megistus (Burmeister) as the outgroup. This outgroup gave evidence that the root of the group would be between T. vitticeps (Stål) and the rest of the species. The placement of T. circummaculata into the middle of the infestans complex is not consistent with the morphological classification, suggesting that the current systematics of this group does not reflect phylogenetic affinities.


Subject(s)
DNA, Mitochondrial/genetics , Evolution, Molecular , Triatoma/classification , Animals , Base Composition , DNA, Ribosomal/genetics , Electron Transport Complex IV/genetics , Genes, Insect , Haplotypes , Models, Genetic , Molecular Sequence Data , Phylogeny , RNA, Ribosomal/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Triatoma/genetics
4.
Am J Trop Med Hyg ; 34(6): 1219-24, 1985 Nov.
Article in English | MEDLINE | ID: mdl-3834804

ABSTRACT

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.


Subject(s)
Aedes/microbiology , Insect Vectors/microbiology , Yellow fever virus/growth & development , Aedes/enzymology , Aedes/genetics , Africa , Animals , Asia , Central America , Female , Genetic Variation , Isoenzymes/analysis , Mouth/microbiology , South America , United States , West Indies
5.
Am J Trop Med Hyg ; 33(3): 492-8, 1984 May.
Article in English | MEDLINE | ID: mdl-6731681

ABSTRACT

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.


Subject(s)
Aedes/genetics , Genetic Variation , Isoenzymes/genetics , Aedes/enzymology , Animals , Gene Frequency , West Indies
7.
J Hered ; 66(4): 203-6, 1975.
Article in English | MEDLINE | ID: mdl-1165399

ABSTRACT

Drosophila pseudoobscura populations of Central Mexico are chromosomally highly polymorphic. Five gene arangements in the third chromosome are endemic, including the two newly described in the present article. The phylogenetic tree of the gene arrangements known in the species is shown in Figure 1. The ones found in Central Mexico all belong to the Santa Cruz "phylad", while in the northern part of the species area both Santa Cruz and Standard phylads are widespread. Some inferences concerning the evolutionary history of the species are presented.


Subject(s)
Chromosomes , Drosophila , Polymorphism, Genetic , Animals , Chromosome Mapping , Genetics, Population , Karyotyping , Mexico
8.
Genetics ; 70(1): 113-39, 1972 Jan.
Article in English | MEDLINE | ID: mdl-5013890

ABSTRACT

We describe allelic variation at 28 gene loci in natural populations of D. willistoni. Seventy samples were studied from localities extending from Mexico and Florida, through Central America, the West Indies, and tropical South America, down to South Brazil. At least several hundred, and often several thousand, genomes were sampled for each locus. We have discovered a great deal of genetic variation. On the average, 58% loci are polymorphic in a given population. (A locus is considered polymorphic when the frequency of the most common allele is no greater than 0.95). An individual fly is heterozygous, on the average, at 18.4% loci.-Concerning the pattern of the variation, the most remarkable finding is the similarity of the configuration of allelic frequencies from locality to locality throughout the distribution of the species. Our observations support the conclusion that balancing natural selection is the major factor responsible for the considerable genetic variation observed in D. willistoni.


Subject(s)
Drosophila/enzymology , Genetic Variation , Genetics, Population , Alleles , Animals , Biological Evolution , Central America , Electrophoresis, Disc , Female , Florida , Gene Frequency , Heterozygote , Isoenzymes/analysis , Male , Mexico , Polymorphism, Genetic , South America
9.
Proc Natl Acad Sci U S A ; 68(10): 2480-3, 1971 Oct.
Article in English | MEDLINE | ID: mdl-5289881

ABSTRACT

A comparative study of genic allozyme and chromosomal polymorphisms in four continental (South American) and six oceanic island (West Indies) populations of Drosophila willistoni has been made. The pattern of genic polymorphism is closely similar in all populations. Although regional and local differences in gene frequencies are found, generally the same alleles occur at high, intermediate, and low frequencies in all populations. An average individual is heterozygous at 18.4 and 16.2% of its loci in the continental and island populations, respectively. By contrast, chromosomal polymorphism is sharply reduced on the islands compared to most continental populations, and some chromosomal inversions are more frequent on some islands than on others. The observations are not compatible with the hypothesis that most of the gene variants are adaptively neutral. Balancing natural selection is responsible for most of the genic polymorphism in natural populations of D. willistoni.


Subject(s)
Drosophila , Enzymes , Gene Frequency , Genes , Polymorphism, Genetic , Alleles , Animals , Chromosome Aberrations , Chromosome Mapping , Electrophoresis, Disc , Enzymes/analysis , Genetic Variation , Heterozygote , South America , West Indies
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