Selection, Recombination and History in a Parasitic Flatworm (Echinococcus) Inferred from Nucleotide Sequences


Autoria(s): Haag,KL; Araújo,AM; Gottstein,B; Zaha,A
Data(s)

01/09/1998

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 analyses revealed several ambiguities, indicating that the taxonomic status of the E. granulosus horse strain should be revised

Formato

text/html

Identificador

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02761998000500024

Idioma(s)

en

Publicador

Instituto Oswaldo Cruz, Ministério da Saúde

Fonte

Memórias do Instituto Oswaldo Cruz v.93 n.5 1998

Palavras-Chave #Echinococcus #parasites #recombination #SSCP #sequencing #phylogeny
Tipo

journal article