Population structure of Dover sole Solea solea: RAPD and allozyme data indicate divergence in European stocks

Abstract

Randomly amplified polymorphic DNA (PCR-RAPD) analysis was used to estimate genetic variation within and between 6 Northeast Atlantic populations of Dover sole Solea solea (L.). A total of 16 fish were randomly selected from each population, and the results were compared with allozyme variation within and between populations. Results from both methods were in general agreement, but the RAPD technique detected higher levels of genetic variation. Contingency analyses (allele frequencies and hierarchical F-ST and non-hierarchical F-DT) indicated highly significant genetic heterogeneity between populations. This result is consistent with the life history of Dover sole, which have homing behavior and discrete spawning grounds. Divergence between populations is indicated by cluster analyses of both allozymes and RAPD data. However, allozymes provided a somewhat better fit of data to predictions (higher values of cophenetic correlation of clusters from the goodness-of-fit statistics) and better correlation between genetic and geographical distances (Mantel's r). Both allozyme and RAPD data indicate that the samples can be clustered into two groups; continental Europe (Bay of Biscay and German Bight) and British Isles (Cumbria, Isle of Man, Ireland and North Sea). Despite the small geographical separation at the closest point, the English Channel may provide a barrier to gene flow between populations of Dover sole around the coasts of Britain and those on the coast of continental Europe.