An examination of the population genetics of Laminaria and other brown algae in the Laminariales using starch gel electrophoresis

While some investigators have attempted to use isozyme electrophoresis to gain information on the genetics of brown algae, most have reported unsatisfactory results. Through exhaustive screening and modification of sample preparation techniques, gel and tray buffers systems, plus staining recipes, we have developed procedures that consistently provide scorable bands for over 20 enzyme systems in several laminarian algae. We have used our procedures to examine geographically diverse populations of Laminaria saccharina and L. longicruris, as well as L. digitata, L. groenlandica, Agarum cribrosum, Alaria esculenta, Chorda tomentosa, and Macrocystis pyrifera. Overall, these kelp species seem to have an extremely low degree of enzyme solymorphism, both within and between populations. While some rare alleles occurred in several enzyme systems, only 3–5 loci were found to be polymorphic. Our results are consistent with the few reported studies that have used molecular genetic techniques to look at the intraspecific variability of laminarian algae. We suggest that at the species level the Laminariales, and perhaps other groups of brown algae, are genetically extremely conservative as compared to other divisions of plants. We further suggest that isozyme electrophoresis provides a quick and useful tool for algal population genetic studies.