The branching pattern of major groups of land plants inferred from parsimony analysis of ribosomal RNA sequences

Barnabas, S. ; Krishnan, S. ; Barnabas, J. (1995) The branching pattern of major groups of land plants inferred from parsimony analysis of ribosomal RNA sequences Journal of Biosciences, 20 (2). pp. 259-272. ISSN 0250-5991

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Official URL: http://www.ias.ac.in/jarch/jbiosci/20/259-272.pdf

Related URL: http://dx.doi.org/10.1007/BF02703273

Abstract

The parsimony and bootstrap branching pattern of major groups of land plants derived from relevant 5S rRNA sequence trees have been discussed in the light of paleobotanical and morphological evidences. Although 5S rRNA sequence information is not useful for dileneating angiosperm relationships, it does capture the earlier phase of land plant evolution. The consensus branching pattern indicates an ancient split of bryophytes and vascular plants from the charophycean algal stem. Among the bryophytes, Marchantia and Lophocolea appear to be phylogenetically close and together with Plagiomnium form a monophyletic group. Lycopodium and Psilotum arose early in vascular land plant evolution, independent of fem-sphenopsid branch. Gymnosperms are polyphyletic; conifers, Gnetales and cycads emerge in that order with ginkgo joining Cycas. Among the conifers, Metasequoia, Juniperus and Taxus emerge as a branch independent of Pinus which joins Gnetales. The phylogeny derived from the available ss-RNA sequences shows that angiosperms are monophyletic with monocots and dicots diverging from a common stem. The nucleotide replacements during angiosperm descent from the gymnosperm ancestor which presumably arose around 370 my ago indicates that monocots and dicots diverged around 180 my ago, which is compatible with the reported divergence estimate of around 200 my ago deduced from chloroplast DNA sequences.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Phylogenetic Analysis; rRNA Sequences; Branching Pattern; Land Plants; Age of Angiosperms
ID Code:2337
Deposited On:07 Oct 2010 09:47
Last Modified:16 May 2016 13:19

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