Selection, recombination and history in a parasitic flatworm (Echinococcus) inferred from nucleotide sequences
Mem. Inst. Oswaldo Cruz
;
93(5): 695-702, Sept.-Oct. 1998. ilus, tab
Artículo
en Inglés
| LILACS
| ID: lil-217863
RESUMO
Three species of flatworms from the genus Echinococcus (E. granulosus, E. multilocularis and E. vogeli) and four strains of E. granulosus (cattle, horse, pig and sheep strains) were analysed by the PCR-SSCP method followed by sequencing, using as targets two non-coding and two coding (one nuclear and one mitochondrial) genomic regions. The sequencing data was used to evaluate hypothesis about the parasite breeding system and the causes of genetic diversification. The calculated recombination parameters suggested that cross-fertilisation was rare in the history of the group. However, the relative rates of substitution in the coding sequences showed that positive selection (instead of purifying selection) drove the evolution of an elastase and neutrophil chemotaxis inhibitor gene (AgB/1). The phylogenetic analysis revealed several ambiguities, indicationg that the taxonomic status of the E. granulosus horse strain should be revised.
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Asunto principal:
Recombinación Genética
/
Secuencia de Bases
/
Polimorfismo Conformacional Retorcido-Simple
/
Echinococcus
Límite:
Animales
Idioma:
Inglés
Revista:
Mem. Inst. Oswaldo Cruz
Asunto de la revista:
Medicina Tropical
/
Parasitología
Año:
1998
Tipo del documento:
Artículo
/
Congreso y conferencia
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