title: Temporal allozyme divergence in infrapopulations of the hemiurid fluke Lecithochirium fusiforme.
abstract: The effect of time on genetic differentiation was studied among infrapopulations of mature specimens of the hemiurid fluke, Lecithochirium fusiforme, a parasite of marine fishes. Genetic distances and genetic structure within and among different temporal samples of a geographical population were investigated using starch gel electrophoresis, by screening 6 polymorphic loci in 2 groups of infrapopulations corresponding to different sampling data, i.e., winter 1997-1998 and autumn 1998. The genetic distance among infrapopulations was low (D = 0.000-0.058 +/- 0.041). However, genetic divergence among infrapopulations from the same geographic location was clearly lower within each temporal sample (G(ST) = 0.021 and 0.034) than the corresponding value obtained for 12 infrapopulations sampled at different seasons of the year (G(ST) = 0.067). These results suggest the existence of a relatively important temporal effect that accounts for the differences in genetic variability among adult infrapopulations of L. fusiforme. Therefore, a hypothetical temporal gene flow favored by the existence of persistent life-cycle stages of this species in paratenic hosts is not sufficient to mask the temporal differentiation caused by genetic drift.
authors.affiliation: Laboratorio de Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Av. Vigo s/n, 15782 Santiago de Compostela, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Vilas
authors.forename: M L
authors.initials: ML
authors.lastname: Sanmartín
authors.forename: E
authors.initials: E
authors.lastname: Paniagua
mesh_terms: D000818:Animals; D004524:Eels / Q000469:parasitology*; D004592:Electrophoresis, Starch Gel / Q000662:veterinary; D005393:Fish Diseases / Q000469:parasitology*; D040961:Genetic Drift; D014644:Genetic Variation; D007527:Isoenzymes / Q000032:analysis / Q000235:genetics; D013997:Time Factors; D014200:Trematoda / Q000201:enzymology / Q000235:genetics*; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary*
chemical_list: D007527:Isoenzymes