Reappraising the theme of breeding systems in Echinococcus: is outcrossing a rare phenomenon?
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.
Haag
K L
KL
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. karen.haag@unibas.ch
Marin
P B
PB
Graichen
D A S
DA
De La Rue
M L
ML
D000818:Animals; D002417:Cattle; D003433:Crosses, Genetic; D004285:Dogs; D048209:Echinococcus granulosus / Q000235:genetics* / Q000502:physiology*; D005838:Genotype; D007178:Inbreeding; D008291:Malate Dehydrogenase / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D012756:Sheep / Q000469:parasitology
D008291:Malate Dehydrogenase