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 reporte d unsatisfactory results. Through exhaustive screening and modificatio n of sample preparation techniques, gel and tray buffers systems, plus staining recipes, we have developed procedures that consistently prov ide scorable bands for over 20 enzyme systems in several laminarian al gae. We have used our procedures to examine geographically diverse pop ulations of Laminaria saccharina and L. longicruris, as well as L. dig itata, L. groenlandica, Agarum cribrosum, Alaria esculenta, Chorda tom entosa, and Macrocystis pyrifera. Overall, these kelp species seem to have an extremely low degree of enzyme polymorphism, both within and b etween populations. While some 'rare alleles' occurred in several enzy me systems, only 3-5 loci were found to be polymorphic. Our results ar e consistent with the few reported studies that have used molecular ge netic techniques to look at the intraspecific variability of laminaria n algae. We suggest that at the species level the Laminariales, and pe rhaps other groups of brown algae, are genetically extremely conservat ive as compared to other divisions of plants. We further suggest that isozyme electrophoresis provides a quick and useful tool for algal pop ulation genetic studies.