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Abstract Detail


Magallón, Susana [1], Quandt, Dietmar [2], Krug, Michael [2], Lewis, Louise [3], Lutzoni, Francois [4].

The diversification of green plants (Viridiplantae).

The evolution of green plants, including their colonization of land, has had momentous consequences on the evolution of life on Earth. Since early in their evolution, green plants successfully occupied marine and fresh-water environments, subsequently adapting to terrestrial life, where they established terrestrial ecosystems, and detonated drastic radiations throughout the tree of life. Based on a thorough study of the fossil record and a broad sampling of the Viridiplantae we estimated divergence times and identified major radiation events for this important group of photoautotrophic organisms. The taxonomic scope of our study consists of 192 species representing all major lineages of chlorophytes, algal streptophytes, bryophytes and tracheophytes, and a rhodophyte outgroup. A maximum likelihood tree was estimated with RAxML based on the sequences of two nuclear and seven plastid markers, which were partitioned and combined to reflect substitution model congruence. Most of the nodes in the resulting phylogenetic hypothesis are strongly supported, and relationships are congruent with those found in recent genomic-scale analyses. In particular, there is a streptophyte grade in which Zygnematales and Charophyceae are most closely related to embryophytes; and a grade of liverworts, mosses and hornworts subtending tracheophytes. The phylogenetic tree was dated with the Bayesian uncorrelated relaxed molecular clock available in BEAST, incorporating ca. 50 fossil-based calibrations that were combined to provide minimum and maximum limits to prior age distributions for internal nodes. The estimated temporal framework indicates that embryophytes evolved ca. 1000 million years after the origin of green plants, and underwent a rapid diversification that gave rise to the major lineages of land plants. A diversification analysis was conducted with Bayesian Analysis of Macroevolutionary Mixtures (BAMM), to identify major changes in diversification rates among phylogenetic lineages and through time. The identified diversification shifts provide an explicit framework to investigate factors potentially associated with radiations and depletions throughout green plant evolution, in concert with other biological lineages.

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1 - Instituto De Biologia, Universidad Nacional Autonoma De Mexico, 3er Circuito De Ciudad Universitaria, Del. Coyoacan, A.P. 70-233, Mexico City, Mexico D.F., N/A, 04510, Mexico
2 - University of Bonn, Nees Institute for Plant Biology, Bonn, Germany
3 - University Of Connecticut, Department Of Ecology & Evolutionary Biology, 75 North Eagleville Rd, Unit 43, Storrs, CT, 06269-3043, USA
4 - Duke University, Department of Biology, Durham, NC, USA

divergence time estimation

Presentation Type: Oral Paper
Session: 10, Macroevolution
Location: 202/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 3:45 PM
Number: 10009
Abstract ID:474
Candidate for Awards:None

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