Single-copy DNA-DNA hybridizations among five species of Laminaria (Phaeophyceae): Phylogenetic and biogeographic implications

Abstract

DNA-DNA hybridizations between single-copy nuclear DNA from Laminaria digitata and total DNA from L. saccharina, L. Hyperborea, L. rodriguezii, L. ochroleuca and Chorda filum, respectively, show that these species of Laminaria are genotypically closely related. Chorda filum is only distantly related with L. digitata. Based on the thermal elution patterns of the DNA hybrids, as quantified by ΔTm(e) values, it is hypothesized that all five species of Laminaria evolved at about the same time from their most recent common ancestor some 15-19 Ma ago. This phylogenetic hypothesis is discussed in relation to the history of modern laminarialean distribution patterns. © 1988 Biologische Anstalt Helgoland.