Phylogenetics and the evolution of major structural characters in the giant genus Euphorbia L. (Euphorbiaceae)

[Display omitted] ► Four major clades of Euphorbia were robustly resolved as successive sister groups. ► Modified growth forms, especially xerophytes, have multiple origins within each of the four major clades. ► Reproductive traits also have a dynamic evolutionary history within Euphorbia. ► The ev...

Full description

Saved in:
Bibliographic Details
Published in:Molecular phylogenetics and evolution 2012-05, Vol.63 (2), p.305-326
Main Authors: Horn, James W., van Ee, Benjamin W., Morawetz, Jeffery J., Riina, Ricarda, Steinmann, Victor W., Berry, Paul E., Wurdack, Kenneth J.
Format: Article
Language:English
Subjects:
Backbone
Base Sequence
Biological Evolution
Character state reconstruction
Cladding
Convergent evolution
Cyathium
DNA
Euphorbia
Euphorbia - anatomy & histology
Euphorbia - classification
Euphorbia - genetics
Euphorbiaceae
Evolution
Evolution, Molecular
Evolutionary
Genetic Markers
genome
Genome, Plant
Genomes
Growth form
inflorescences
leaves
Molecular Sequence Data
Multigene analyses
nucleotide sequences
Origins
Phylogeny
Plant Leaves - anatomy & histology
Plants (organisms)
Seeds - anatomy & histology
Seeds - genetics
Sequence Analysis, DNA
topology
Vegetation
vegetation types
Xerophyte
xerophytes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:[Display omitted] ► Four major clades of Euphorbia were robustly resolved as successive sister groups. ► Modified growth forms, especially xerophytes, have multiple origins within each of the four major clades. ► Reproductive traits also have a dynamic evolutionary history within Euphorbia. ► The evolution of growth form and inflorescence position are significantly correlated. ► A pathway of transitions for those correlated traits has implications for the evolution of large Euphorbia xerophytes. Euphorbia is among the largest genera of angiosperms, with about 2000 species that are renowned for their remarkably diverse growth forms. To clarify phylogenetic relationships in the genus, we used maximum likelihood, Bayesian, and parsimony analyses of DNA sequence data from 10 markers representing all three plant genomes, averaging more than 16kbp for each accession. Taxon sampling included 176 representatives from Euphorbioideae (including 161 of Euphorbia). Analyses of these data robustly resolve a backbone topology of four major, subgeneric clades—Esula, Rhizanthium, Euphorbia, and Chamaesyce—that are successively sister lineages. Ancestral state reconstructions of six reproductive and growth form characters indicate that the earliest Euphorbia species were likely woody, non-succulent plants with helically arranged leaves and 5-glanded cyathia in terminal inflorescences. The highly modified growth forms and reproductive features in Euphorbia have independent origins within the subgeneric clades. Examples of extreme parallelism in trait evolution include at least 14 origins of xeromorphic growth forms and at least 13 origins of seed caruncles. The evolution of growth form and inflorescence position are significantly correlated, and a pathway of evolutionary transitions is supported that has implications for the evolution of Euphorbia xerophytes of large stature. Such xerophytes total more than 400 species and are dominants of vegetation types throughout much of arid Africa and Madagascar.
ISSN:1055-7903
1095-9513
DOI:10.1016/j.ympev.2011.12.022