The occurrence and significance of triploidy in the liver fluke, Fasciola hepatica

H. L. FLETCHER a1c1, E. M. HOEY a1, N. ORR a1p1, A. TRUDGETT a1, I. FAIRWEATHER a1 and M. W. ROBINSON a1p2
a1 Parasite Proteomics and Therapeutics Research Group, The Queen's University of Belfast, School of Biology and Biochemistry, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK

Article author query
fletcher h   [PubMed][Google Scholar] 
hoey e   [PubMed][Google Scholar] 
orr n   [PubMed][Google Scholar] 
trudgett a   [PubMed][Google Scholar] 
fairweather i   [PubMed][Google Scholar] 
robinson m   [PubMed][Google Scholar] 


Karyotyping of Fasciola hepatica samples from Britain and Ireland has identified a triploid isolate which is effectively aspermic, rendering it necessarily asexually reproducing. Considering the extensive presence of asexually reproducing diploid and triploid Fasciola in Asia it is suggested that facultative gynogenesis is widespread in this parasite. This has important implications for the population genetics and evolution of Fasciola, especially in relation to the development and spread of drug resistance, and must be considered in the mathematical modelling of this process.

(Received June 7 2003)
(Revised August 11 2003)
(Accepted August 11 2003)

Key Words: Fasciola hepatica; triploidy; karyotype; parthenogenesis; drug resistance.

c1 Tel: +44 2890 272084. Fax: +44 2890 335877. E-mail:
p1 Present address: Department of Haematology, ‘C’ Floor, Belfast City Hospital, 51 Lisburn Road, Belfast BT9 7AB.
p2 Present address: The Queen's University of Belfast, The Dept. of Veterinary Science, Stoney Road, Stormont, Belfast BT4 3SD.