Two Hybridization Events Define the Population Structure of Trypanosoma cruzi
| Autor: | David A. Campbell, Christian Barnabé, Nancy R. Sturm, Scott J. Westenberger |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Trypanosoma cruzi
Genes Protozoan Molecular Sequence Data Locus (genetics) Investigations Biology Polymorphism Single Nucleotide Genome Evolution Molecular Loss of heterozygosity Species Specificity Genetic variation Genotype Genetics Animals Cluster Analysis Typing Allele Phylogeny Base Sequence Models Genetic Genetic Variation Sequence Analysis DNA biology.organism_classification Genetics Population Hybridization Genetic Sequence Alignment Polymorphism Restriction Fragment Length |
| Zdroj: | Genetics. 171:527-543 |
| ISSN: | 1943-2631 |
| DOI: | 10.1534/genetics.104.038745 |
| Popis: | Genetic variation in Trypanosoma cruzi is likely a key determinant in transmission and pathogenesis of Chagas disease. We have examined nine loci as markers for the extant T. cruzi strains. Four distinct alleles were found for each locus, corresponding to the sequence classes present in the homozygous discrete typing units (DTUs) I, IIa, IIb, and IIc. The alleles in DTUs IIa and IIc showed a spectrum of polymorphism ranging from DTU I-like to DTU IIb-like, in addition to DTU-specific sequence variation. DTUs IId and IIe were indistinguishable, showing DTU homozygosity at one locus and heterozygosity with DTU IIb and IIc allelic sequences at eight loci. Recombination between the DTU IIb and IIc alleles is evidenced from mosaic polymorphisms. These data imply that two discrete hybridization events resulted in the formation of the current DTUs. We propose a model in which a fusion between ancestral DTU I and IIb strains gave rise to a heterozygous hybrid that homogenized its genome to become the homozygous progenitor of DTUs IIa and IIc. The second hybridization between DTU IIb and IIc strains that generated DTUs IId and IIe resulted in extensive heterozygosity with subsequent recombination of parental genotypes. |
| Databáze: | OpenAIRE |
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