TRACKING DISPERSAL ROUTES - PHYLOGEOGRAPHY OF THE ARCTIC ANTARCTIC DISJUNCT SEAWEED ACROSIPHONIA-ARCTA (CHLOROPHYTA)

Abstract

Phylogenetic relationships in the Arctic‐Antarctic disjunct seaweed species Acrosiphonia arcta (Dillwyn) J. G. Agardh (Acrosiphoniales, Chlorophyta) were examined using restriction fragment‐length polymorphism analysis of the fast‐evolving nuclear ribosomal intergenic spacer (IGS) region and random amplified polymorphic DNA (RAPD) markers. Twenty‐two isolates collected from 10 different locations in both hemispheres were compared. Five IGS length classes were identified among the 10 locations. Throughout the North Atlantic, IGS regions were found to be extremely homogeneous whereas RAPD patterns revealed subdivided populations that suggest founder effects. Acrosiphonia arcta populations foun..