An Investigation of the Genetic Variation in Four Fucales Species Using Cellulose Acetate Electrophoresis

Abstract

A cellulose acetate electrophoresis method was used to examine allozyme variation both within and between three members of the genus Fucus: F. spiralis, F. vesiculosus and F. serratus and Ascophyllum nodosum. Samples of algae were collected from two rocky shores, one sheltered and one exposed, 11 km apart and screened for allozyme variation at eight loci. Patterns of allozyme variation at five polymorphic loci were successfully resolved. There was significant heterogeneity in allele frequencies between both the F. serratus and F. spiralis populations from the two shores but not between the two F. vesiculosus populations. In the fucoids, there was an overall heterozygote deficiency within populations relative to Hardy Weinberg proportions and FIT values were high. There was little genetic differentiation between the populations of each species, however Fucus serratus showed the greatest (F_ST = 0.0261) and F. vesiculosus the least amount (F_ST = 0.0058) of genetic differentiation between shores. Based upon UPGMA clustering of Nei's genetic identities, F. spiralis was the most genetically distinct and F. serratus clustered with F. vesiculosus. Ascophyllum nodosum joined the main Fucus cluster as an outgroup confirming that it is genetically quite distinct from the members of the genus Fucus. Based on our results we suggest that cellulose acetate electrophoresis is a suitable tool for the elucidation of population genetic patterns in the brown algae.