Genetic characterization of populations of the ectoparasitic caligid, Lepeophtheirus salmonis (Kroyer 1837) using randomly amplified polymorphic DNA

Genetic variability within salmon louse, Lepeophtheirus salmonis (Caligidae: Copepoda), populations parasitizing farmed and wild Scottish Atlantic salmon (Salmo salar) was investigated using analysis of randomly amplified polymorphic DNA (RAPD) fragments. Seven individual decamer primers were used to analyse samples of salmon lice collected from 15 different locations in Scotland. The polymerase chain reaction products were separated using agarose gel electrophoresis and the resulting band patterns were analysed using a semi-automated analytical scoring system. Dendrograms were produced using the unweighted pair-group average (UPGMA) method using Dice similarity values. The summary dendrogram of the analysis of all RAPD bands showed two separate clusters of salmon lice, the larger being sub-divided into a further two sections. The collections of lice occupying each of these sub-divisions, however, were a mix of sites, which did not exhibit a structured geographical pattern.