ibclogo XVI International Botanical Congess

Abstract Number: 3606
Poster No. = 19


PHYLOGENETICS OF ACROCHAETIALES BASED ON CHLOROPLAST 23S rDNA SEQUENCES


M.E. Volovsek, M.H. Hommersand and P.S. Manos. Dept. of Biology, UNC-CH, Chapel Hill, NC 27599, Dept. of Botany, Duke University, Durham, NC 27708


Acrochaetiales comprises an assemblage of reproductively simple filamentous red algae whose ordinal and familial level systematics remain unclear. RbcL (Volovsek et al, 1997) and 18S rDNA (Harper and Saunders, 1998) phylogenies support two major lineages but are unable to determine their relationship. Preliminary cp23S rDNA sequences provide deeper phylogenetic resolution, supporting a sister relationship between one of the acrochaetialean lineages and Palmariales, and a monophyletic Acrochaetiales-Palmariales complex. Well supported tree topologies situate the Acrochaetiales-Palmariales complex terminally within a nemalialean assemblage and suggest that simple reproductive features characteristic of Acrochaetiales and Palmariales are homologous and may represent a reduction trend.

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