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Reappraising the theme of breeding systems in Echinococcus: is outcrossing a rare phenomenon?

Published online by Cambridge University Press:  30 September 2010

K. L. HAAG*
Affiliation:
Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul. Caixa Postal 15053, CEP 91501-970, Porto Alegre, Brazil Departamento de Genética, Universidade Federal do Rio Grande do Sul. Caixa Postal 15053, CEP 91501-970, Porto Alegre, Brazil University of Basel, Zoological Institute, Vesalgasse 1, 4051 Basel, Switzerland
P. B. MARIN
Affiliation:
Departamento de Genética, Universidade Federal do Rio Grande do Sul. Caixa Postal 15053, CEP 91501-970, Porto Alegre, Brazil
D. A. S. GRAICHEN
Affiliation:
Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul. Caixa Postal 15053, CEP 91501-970, Porto Alegre, Brazil
M. L. DE LA RUE
Affiliation:
Departamento de Microbiologia e Parasitologia/CCS, Universidade Federal de Santa Maria. Av. Roraima, 1000, CEP 97105-900, Santa Maria, Brazil
*
*Corresponding author: University of Basel, Zoological Institute, Vesalgasse 1, 4051 Basel, Switzerland. Tel: +41 (0) 61 267 03 61. Fax: +41 (0) 61 267 03 62. E-mail: karen.haag@unibas.ch

Summary

Selfing has been considered the most common mode of reproduction in Echinococcus flatworms. However, population genetic studies on the asexual larval stage involving nuclear co-dominant markers have not always revealed significant heterozygote deficiencies – the expected outcome of a regularly and highly inbred population. In this study, we analysed the genetic structure of Echinococcus granulosus sensu lato populations from Southern Brazil during their adult (sexual) stage using 1 mitochondrial and 1 nuclear marker (cox 1 and mdh, respectively). We show that parasite genetic differentiation is largest among definitive hosts (domestic dogs) from different farms, suggesting that transmission is mostly maintained within a farm. Moreover, we show that heterozygote deficiencies are not significant, and we suggest that outbreeding is the most common mode of reproduction of the parasite in that region.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2010

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