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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An electrophoretic survey of 42 populations of Anopheles pseudopunctipennis collected throughout its known geographic distribution was performed to clarify the taxonomic status of this important malaria vector species. The results indicated strong differences in the allele frequencies of three enzyme loci (glycerol dehydrogenase, 6-phosphogluconate dehydrogenase, and phosphoglucomutase) of the 33 loci analyzed. No fixed electromorphic differences separate the populations of An. pseudopunctipennis. The populations of An. pseudopunctipennis showed little genetic divergence, with Nei distances ranging from 0 to 0.079. A comparison of An. pseudopunctipennis data with either one of three other Anopheles species showed a high genetic distance of 0.335 with a closely related species, An. franciscanus; 0.997 with An. crucians, and 2.355 with An. (Nyssorhynchus) albimanus. Geographic populations of An. pseudopunctipennis were classified into three clusters; one cluster included populations collected in North America (United States and Mexico) and Guatemala, one cluster included populations from Belize and South America (Colombia, Ecuador, Peru, Chile, and Argentina); and one cluster was represented by populations from the Island of Grenada (type-locality of An. pseudopunctipennis). Based on our isozyme analyses, we defined these clusters as three geographic populations of An. pseudopunctipennis. Of the two mainland populations, one extends from the southern United States south through Mexico and Guatemala, and the other extends north from southern South America through Central America to Belize. These two geographic populations converge in southern Mexico and northern Central America. One part of the convergence zone was identified in the area of eastern Guatemala and southern Belize.
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PMID:Biochemical systematics and population genetic structure of Anopheles pseudopunctipennis, vector of malaria in Central and South America. 748 88

Enzyme electrophoresis and restriction fragment length polymorphism (RFLP) analysis of Anopheles pseudopunctipennis sensu lato from nine isolated populations in neotropical America confirmed previous observations that it constitutes a species complex. Electrophoretic studies showed fixed differences at two enzyme loci, glycerol dehydrogenase (Gcd) and phosphoglucomutase (Pgm), suggesting limited or no gene flow between populations from Mexico and South America. In addition, analysis of genetic distance showed two distinctive clusters, one from Mexico and the other from South America, separated at a Nei's distance level of 0.13, a value consistent in magnitude with that of other anopheline sibling species. The RFLP analysis revealed the presence of a ribosomal DNA fragment in Mexican strains that was absent in strains from South America. Two species have been identified through these studies, one provisionally named An. pseudopunctipennis A, a species from central Mexico, and the other An. pseudopunctipennis B, for the species found in the interAndean valleys and Andean slopes in regions of Peru and Bolivia. This research provides information required to elucidate the status of the different species of the An. pseudopunctipennis complex as vectors of malaria in the Americas.
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PMID:Characterization of Anopheles pseudopunctipennis sensu lato from three countries of neotropical America from variation in allozymes and ribosomal DNA. 790 29

A genetic and morphologic survey of Anopheles darlingi populations collected from seven countries in Central and South America was performed to clarify the taxonomic status of this major malaria vector species in the Americas. Population genetics was based on three techniques including isozyme, random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), and internal transcribed spacer 2 (ITS2) markers. The results of the isozyme analysis indicated moderate differences in the allele frequencies of three putative loci (glutamate oxalaoacetate transaminase-1, isocitrate dehydrogenase-1, and phosphoglucomutase) of the 31 analyzed. No fixed electromorphic differences separated the populations of An. darlingi, which showed little genetic divergence (Nei distances = 0.976-0.995). Fragments produced by RAPD-PCR demonstrated evidence of geographic partitioning and showed that all populations were separated by small genetic distances as measured with the 1 - S distance matrix. The ITS2 sequences for all samples were identical except for four individuals from Belize that differed by a three-base deletion (CCC). The morphologic study demonstrated that the Euclidean distances ranged from 0.02 to 0.14, with the highest value observed between populations from Belize and Bolivia. Based on these analyses, all the An. darlingi populations examined demonstrated a genetic similarity that is consistent with the existence of a single species and suggest that gene flow is occurring throughout the species' geographic range.
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PMID:Population structure of the primary malaria vector in South America, Anopheles darlingi, using isozyme, random amplified polymorphic DNA, internal transcribed spacer 2, and morphologic markers. 1046 62

Almost all individuals (182) belonging to an Amazonian riverine population (Portuchuelo, RO, Brazil) were investigated for ascertaining data on epidemiological aspects of malaria. Thirteen genetic blood polymorphisms were investigated (ABO, MNSs, Rh, Kell, and Duffy systems, haptoglobins, hemoglobins, and the enzymes glucose-6-phosphate dehydrogenase, glyoxalase, phosphoglucomutase, carbonic anhydrase, red cell acid phosphatase, and esterase D). The results indicated that the Duffy system is associated with susceptibility to malaria, as observed in other endemic areas. Moreover, suggestions also arose indicating that the EsD and Rh loci may be significantly associated with resistance to malaria. If statistical type II errors and sample stratification could be ruled out, hypotheses on the existence of a causal mechanism or an unknown closely linked locus involved in susceptibility to malaria infection may explain the present findings.
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PMID:The association of genetic markers and malaria infection in the Brazilian Western Amazonian region. 1293 53