Infraspecific phylogeny of Pandorina morum (Volvocales, Chlorophyta) inferred from molecular, biochemical and traditional data

Molecular phylogenetic relationships among sexually isolated subpopulations (syngens) of the morphologically defined volvocacean flagellate Pandorina morum (O. F. Muller) Bory are inferred from sequences of the internal trans cribed spacer regions (ITS-1 and ITS-2) of the nuclear ribosomal DNA repeat s. The resolved phylogenetic lines are composed of strains with very simila r sets of traditional characters, such as zygote aggregation pattern, chrom osome number and cell division timing, and are correlated with the distribu tion pattern of the xanthophyll loroxanthin [(3R,3'R,6'R)-beta,epsilon-caro tene-3,19,3'-triol]. Thus, loroxanthin, a phylogenetic character within the Volvocales. is also of value at the infraspecific level in P. morum, a mor phologically uniform species complex, within the Volvocales.