title: Temporal genetic variation of Fasciola hepatica from sheep in Galicia (NW Spain).
abstract: We found low genetic differentiation between two temporal samples of Fasciola hepatica (2006 and 2008) collected from nine sheep of the same flock that shared the same pasture for at least 2 years. However, each sample, represented by four and five infrapopulations respectively, showed strong heterozygote deficits regarding Hardy-Weinberg expectations and a high degree of genetic structure at infrapopulation level. This is an unexpected result since genetic drift should increase temporal variation among years. Our findings are most likely explained by the fact that the parasite can survive many years in the definitive host. Temporal gene flow favored by high longevity probably increases levels of genetic variability of the population but could also contribute to the observed heterozygote deficits within temporal samples and infrapopulations if it favors the Wahlund effect. Despite the homogenizing effect of gene flow, the high genetic divergence observed between infrapopulations is most likely a consequence of strong genetic drift associated to the complexity of the life cycle.
authors.affiliation: Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Av. Alemania 01090, 4810101 Temuco, Chile; Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain. Electronic address: severovazquezprieto@gmail.com.
authors.forename: Severo
authors.initials: S
authors.lastname: Vázquez-Prieto
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad de Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain.
authors.forename: Román
authors.initials: R
authors.lastname: Vilas
authors.affiliation: Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain.
authors.forename: Florencio M
authors.initials: FM
authors.lastname: Ubeira
authors.affiliation: Laboratorio de Parasitología, Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Campus Vida, 15782 Santiago de Compostela, Spain.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Paniagua
mesh_terms: D000818:Animals; D005210:Fasciola hepatica / Q000235:genetics*; D005211:Fascioliasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D005786:Gene Expression Regulation / Q000502:physiology; D014644:Genetic Variation; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000469:parasitology*; D013030:Spain / Q000453:epidemiology; D013997:Time Factors
chemical_list: D015801:Helminth Proteins
keywords: Allozymes; Fasciola hepatica; Microsatellites; Population genetic structure; Temporal variation