title: The evolutionary root of flowering plants.
abstract: Correct rooting of the angiosperm radiation is both challenging and necessary for understanding the origins and evolution of physiological and phenotypic traits in flowering plants. The problem is known to be difficult due to the large genetic distance separating flowering plants from other seed plants and the sparse taxon sampling among basal angiosperms. Here, we provide further evidence for concern over substitution model misspecification in analyses of chloroplast DNA sequences. We show that support for Amborella as the sole representative of the most basal angiosperm lineage is founded on sequence site patterns poorly described by time-reversible substitution models. Improving the fit between sequence data and substitution model identifies Trithuria, Nymphaeaceae, and Amborella as surviving relatives of the most basal lineage of flowering plants. This finding indicates that aquatic and herbaceous species dominate the earliest extant lineage of flowering plants. [; ; ; ; ; .].
authors.affiliation: IASMA Research Center, Via E. Mach 1, 38010 San Michele all'Adige (TN), Italy. Vadim.Goremykin@iasma.it
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Goremykin
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Nikiforova
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Biggs
authors.forename: Bojian
authors.initials: B
authors.lastname: Zhong
authors.forename: Peter
authors.initials: P
authors.lastname: Delange
authors.forename: William
authors.initials: W
authors.lastname: Martin
authors.forename: Stefan
authors.initials: S
authors.lastname: Woetzel
authors.forename: Robin A
authors.initials: RA
authors.lastname: Atherton
authors.forename: Patricia A
authors.initials: PA
authors.lastname: McLenachan
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lockhart
mesh_terms: D018742:DNA, Chloroplast / Q000235:genetics; D018740:Genetic Heterogeneity; D019684:Magnoliopsida / Q000145:classification* / Q000235:genetics*; D008957:Models, Genetic; D010802:Phylogeny; D016415:Sequence Alignment; D064028:Tracheophyta / Q000145:classification / Q000235:genetics
chemical_list: D018742:DNA, Chloroplast