A Cladistic Approach to the Phylogeny of the "Bryophytes"

Mishler, Brendt D.; Churchill, Steven P.

doi:10.2307/2806602

Cited by 199 publications

(180 citation statements)

References 39 publications

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“…In alternative topology test analyses of the multigene supermatrix, we were initially unable to reject the three competing hypotheses: mosses sister to vascular plants (5,6), hornworts basal (14,15), and bryophytes monophyletic (13,16,17), although the first two were close to the rejection threshold under ML (Tables 1 and 2, which are published as supporting information on the PNAS web site). We implemented a second constraint search in which relationships within the four major land plant clades were constrained based on the 50% majority BS trees obtained from ML and MP analyses.…”

Section: Resultsmentioning

confidence: 99%

The deepest divergences in land plants inferred from phylogenomic evidence

Qiu

Wang

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

575

490

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Phylogenetic relationships among the four major lineages of land plants (liverworts, mosses, hornworts, and vascular plants) remain vigorously contested; their resolution is essential to our understanding of the origin and early evolution of land plants. We analyzed three different complementary data sets: a multigene supermatrix, a genomic structural character matrix, and a chloroplast genome sequence matrix, using maximum likelihood, maximum parsimony, and compatibility methods. Analyses of all three data sets strongly supported liverworts as the sister to all other land plants, and analyses of the multigene and chloroplast genome matrices provided moderate to strong support for hornworts as the sister to vascular plants. These results highlight the important roles of liverworts and hornworts in two major events of plant evolution: the water-to-land transition and the change from a haploid gametophyte generation-dominant life cycle in bryophytes to a diploid sporophyte generation-dominant life cycle in vascular plants. This study also demonstrates the importance of using a multifaceted approach to resolve difficult nodes in the tree of life. In particular, it is shown here that densely sampled taxon trees built with multiple genes provide an indispensable test of taxon-sparse trees inferred from genome sequences.alternation of generations ͉ hornworts ͉ liverworts ͉ phylogeny ͉ taxon sampling T he origin and early evolution of land plants (embryophytes) during the mid-Ordovician to lower Silurian (480-430 million years ago) initiated the establishment of the modern terrestrial ecosystems and fundamentally altered the course of evolution of life on earth. Two important events marked this period of unprecedented innovation in plant evolution: the massive colonization of the land by plants descended from charophyte algae and the change of the dominant generation in the plant life cycle from a haploid gametophyte to a diploid sporophyte (1-5). The first event opened a vastly underexplored niche of high-intensity solar radiation and abundant CO 2 to photosynthetic life. The second event conferred on plants two abilities to adapt to a life in a water-deficient and UV-abundant terrestrial environment. One is the ability to produce a large number of genetically diverse gametes to ensure fertilization on land where sperm locomotion is hindered, and the other is the ability to mask deleterious mutations through the dominantrecessive interaction of alleles, thus allowing a large number of alleles to persist in the gene pool (2-4). Our understanding of these events hinges on our knowledge of relationships between the organisms involved in these major evolutionary transitions. Despite numerous studies using diverse approaches analyzing morphological and͞or molecular characters, relationships among early land plants remain controversial (5-19). Fossil evidence, although increasingly improved, has not helped to resolve the issues decisively (20,21).A multitude of phenomena characterizing diversification of many major clades o...

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Section: Resultsmentioning

confidence: 99%

The deepest divergences in land plants inferred from phylogenomic evidence

Qiu

Wang

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

575

490

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“…The phylogenetic tree of tracheophytes used in this study is the ML tree of Pryer et al (21) inferred from analysis of the plastid genes rbcL, atpB, and rps4 and nuclear 18S ribosomal DNA (Fig. 1) (25,26), the distribution of introns (27), and some DNA sequence data sets (e.g., ref. 28)]; basal polytomy, as reported by Pryer et al (21).…”

Section: Methodsmentioning

confidence: 99%

Rate heterogeneity among lineages of tracheophytes: Integration of molecular and fossil data and evidence for molecular living fossils

Soltis

Savolainen

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

232

152

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Many efforts to date evolutionary divergences by using a molecular clock have yielded age estimates that are grossly inconsistent with the paleontological evidence. Such discrepancies often are attributed to the inadequacy of the fossil record, but many potential sources of error can affect molecular-based estimates. In this study, we minimize the potential error caused by inaccurate topology and uncertain calibration times by using a well-supported tree, multiple genes, and multiple well-substantiated dates to explore the correspondence between the fossil record and molecular-based age estimates for major clades of tracheophytes. Age estimates varied because of gene effects, codon position, lineage effects, method of inferring branch lengths, and whether or not rate constancy was assumed. However, even methods designed to ameliorate the effects of rate heterogeneity among lineages could not accommodate the substantially slower rates observed in Marattia ؉ Angiopteris and in the tree ferns. Both of these clades of ferns have undergone dramatic decelerations in their rates of molecular evolution and are ''molecular living fossils,'' consistent with their relative morphological stasis for the past 165-200 million years. Similar discrepancies between the fossil record and molecular-based age estimates noted in other studies may also be explained in part by violations of rate constancy among lineages.

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“…Phylogenetic relationships of Polytrichales are particularly relevant to considerations of the evolutionary history of mosses since the group is probably among the first of the lineages that diverged from the common ancestor of all mosses (Mishler and Churchill, 1984). Earlier cladistic analyses of the group have been done by Hyv€ onen (1989), Forrest (1995), andHyv€ onen et al (1998).…”

Section: Introductionmentioning

confidence: 99%