rbcL sequences: a promising tool for the molecular systematics of the fern genus Trichomanes (Hymenophyllaceae)?
A phylogenetic study using rbcL sequences was performed on 18 species of the fern genus Trichomanes (Hymenophyllaceae) in order to (i) test the ability of this gene for resolving relationships within this taxon and (ii) reveal major phylogenetic tendencies. Molecular divergence values suggest that subtaxa of this genus more closely conform to generic concepts as applied to other ferns and angiosperms. Although the gene rbcL appears to be a promising tool, the deepest relationships remain ambiguous, probably in relation with saturation, especially for transition events. Despite the taxonomic undersampling, some major systematic tendencies are evidenced. Morton's subgenus Didymoglossum appears to be strongly supported. The monotypic section Davalliopsis and subgenus Achomanes cluster together into an unexpected geographic group. The monophyly of each of Morton's subgenera Trichomanes and Pachychaetum is not retrieved. Molecular data seem in fact to be more in agreement with comparative cytology rather than with morphology. Additional taxa are suggested for confirming these tendencies.
Dubuisson
J
J
Laboratoire de Paléobotanique, Institut des Sciences de l'Evolution, Montpellier Cedex 5, F 34095, France.
D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D017753:Ecosystem; D019143:Evolution, Molecular; D017343:Genes, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000145:classification* / Q000235:genetics*; D012273:Ribulose-Bisphosphate Carboxylase
D018744:DNA, Plant; D010940:Plant Proteins; C101625:RbcL protein, plastid; D012273:Ribulose-Bisphosphate Carboxylase