title: Seasonal and Cyclical Changes in Genetic Composition of the Marine Intertidal Rock Pool Copepod Tigriopus brevicornis.
abstract: Tigriopus brevicornis is a marine rock pool copepod widely distributed along Atlantic coasts. Due to the absence of a known dispersal mechanism by free swimming stages, exchanges between populations over long distances are questionable. In order to analyse the evolution of an isolated supralittoral rock pool population, sampling of the copepod was performed monthly during 1 year and compared to samplings over 5 years in the same rock pool, as well as from other rock pools. Using ITS1 analysis, cyclical changes in genetic composition were detected. Our results give clear indications concerning the segregation of the rock pool population and a lack of gene flow among outside populations. A network analysis shows the presence of several shared dominant haplotypes and also singletons differing by one mutation point. F(st) analyses indicate that the main changes occur in autumn and winter. The few analogies of ITS1 sequences with nearby populations may indicate that new migrants must re-colonise the pools from surrounding rock crevices in the intertidal habitat where they may have found a refuge after bad weather conditions.
authors.affiliation: UMR 7208 BOREA, Station de Biologie Marine, Muséum National d'Histoire Naturelle, Place de La Croix, BP 225, 29900, Concarneau, France, avw@mnhn.fr.
authors.forename: Alain
authors.initials: A
authors.lastname: Van Wormhoudt
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D033342:Copepoda / Q000235:genetics*; D051456:Gene Flow; D005828:Genetics, Population; D012621:Seasons