title: The Small Nuclear Genomes of Selaginella Are Associated with a Low Rate of Genome Size Evolution.
abstract: The haploid nuclear genome size (1C DNA) of vascular land plants varies over several orders of magnitude. Much of this observed diversity in genome size is due to the proliferation and deletion of transposable elements. To date, all vascular land plant lineages with extremely small nuclear genomes represent recently derived states, having ancestors with much larger genome sizes. The Selaginellaceae represent an ancient lineage with extremely small genomes. It is unclear how small nuclear genomes evolved in Selaginella We compared the rates of nuclear genome size evolution in Selaginella and major vascular plant clades in a comparative phylogenetic framework. For the analyses, we collected 29 new flow cytometry estimates of haploid genome size in Selaginella to augment publicly available data. Selaginella possess some of the smallest known haploid nuclear genome sizes, as well as the lowest rate of genome size evolution observed across all vascular land plants included in our analyses. Additionally, our analyses provide strong support for a history of haploid nuclear genome size stasis in Selaginella Our results indicate that Selaginella, similar to other early diverging lineages of vascular land plants, has relatively low rates of genome size evolution. Further, our analyses highlight that a rapid transition to a small genome size is only one route to an extremely small genome.
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Arizona abaniaga@email.arizona.edu.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Baniaga
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Arizona Department of Ecology & Evolution, University of Lausanne, Switzerland.
authors.forename: Nils
authors.initials: N
authors.lastname: Arrigo
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Arizona.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Barker
mesh_terms: D004251:DNA Transposable Elements / Q000235:genetics; D019143:Evolution, Molecular; D059646:Genome Size; D018745:Genome, Plant; D006238:Haploidy; D032503:Selaginellaceae / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements
keywords: Selaginella; Selaginellaceae; evolution; flow cytometry; genome size; lycophytes