Learn More
Simple phylogenetic tests were applied to a large data set of nucleotide sequences from two nuclear genes and a region of the mitochondrial genome of Trypanosoma cruzi, the agent of Chagas' disease. Incongruent gene genealogies manifest genetic exchange among distantly related lineages of T. cruzi. Two widely distributed isoenzyme types of T. cruzi are(More)
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(More)
A genetic interpretation of the zymograms of 524 Trypanosoma cruzi stocks from various hosts and representing a broad geographical range (United States to Southern Brazil) reveals high genetic variability (only one monomorphic locus out of 15) and suggests that this parasite has a diploid structure. The data do not give any indication of Mendelian(More)
DNA sequence variation in a 1410-bp region including the Cu,Zn Sod locus was examined in 41 homozygous lines of Drosophila melanogaster. Fourteen lines were from Barcelona, Spain, 25 were from California populations and the other two were from laboratory stocks. Two common electromorphs, SODS and SODF, are segregating in the populations. Our sample of 41(More)
We have explored the evolutionary history of the Apicomplexa and two related protistan phyla, Dinozoa and Ciliophora, by comparing the nucleotide sequences of small subunit ribosomal RNA genes. We conclude that the Plasmodium lineage, to which the malarial parasites belong, diverged from other apicomplexan lineages (piroplasmids and coccidians) several(More)
We have studied 15 gene loci coding for enzymes in 121 Trypanosoma cruzi stocks from a wide geographic range--from the United States and Mexico to Chile and southern Brazil. T. cruzi is diploid but reproduction is basically clonal, with very little if any sexuality remaining at present. We have identified 43 different clones by their genetic composition;(More)
We have assayed genetic polymorphisms in several species of parasitic protozoa by means of random amplified polymorphic DNA (RAPD). One goal was to ascertain the suitability of RAPD markers for investigating genetic and evolutionary problems, particularly in organisms, such as the parasitic protozoa, unsuitable for traditional methods of genetic analysis.(More)
Density-dependent genetic evolution was tested in experimental populations of Drosophila melanogaster subject for eight generations to natural selection under high (K-selection) or low (r-selection) population density regimes. The test consisted of determining at high and at low densities the per capita rate of population growth of the selected populations.(More)
Drosophila species are extensively used in biological research; yet, important phylogenetic relationships within the genus and with related genera remain unresolved. The combined data for three genes (Adh, Sod, and Gpdh) statistically resolves outstanding issues. We define the genus Drosophila inclusively so as to include Scaptomyza and Zaprionus(More)