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Population genetic structure of the prosobranch Nassarius reticulatus (L.) in a ria seascape (NW Iberian Peninsula) as revealed by RAPD analysis

Barreiro, Rodolfo, Couceiro, Lucia, Quintela, María, Ruiz, José Miguel
Marine biology 2006 v.148 no.5 pp. 1051-1060
Nassarius reticulatus, coasts, estuaries, genetic distance, genetic heterogeneity, habitats, multidimensional scaling, random amplified polymorphic DNA technique, rivers, valleys, variance, Iberian Peninsula
Randomly amplified polymorphic DNA (RAPD) banding patterns were compared between samples of the netted dogwhelk Nassarius reticulatus from 11 locations along the NW Iberian Peninsula coast. To detect if rias (estuaries formed by drowned river valleys) might promote genetic differentiation, five sampling sites were located within a ria (ria of Muros) and the remaining six were scattered along open-coast areas at increasing distances from the ria mouth. Population differentiation statistics (Φ-values) were estimated using a hierarchical analysis of molecular variance (AMOVA) with samples sorted into two groups: open-coast and ria populations. Despite a high potential to disperse, AMOVA demonstrated a modest, statistically significant genetic heterogeneity among N. reticulatus populations. Most of the genetic structure resided in differences among open-coast populations; ria populations were genetically homogeneous. No obvious geographical pattern was detected for the pairwise genetic distances (non-metric multidimensional scaling; UPGMA tree; Mantel test). Unlike previous studies with other species at a variety of estuarine systems other than rias, there was no evidence that the ria of Muros may enhance the genetic divergence of N. reticulatus populations. This discrepancy is discussed in relation to the biological features of the species (high dispersal potential and a preference for mid-low estuarine habitat) and the strong hydrographic connectivity between ria and neighbouring off-shore waters.