Polyploidy does not control all: Lineage‐specific average chromosome length constrains genome size evolution in ferns
Resource type
Journal article
Creator (person)
Liu, Hong‐Mei
Ekrt, Libor
Koutecky, Petr
Pellicer, Jaume
Hidalgo, Oriane
Marquardt, Jeannine
Pustahija, Fatima
Ebihara, Atsushi
Siljak‐Yakovlev, Sonja
Gibby, Mary
Leitch, Ilia
Schneider, Harald
Date published
August 9, 2019
Abstract
Recent studies investigating the evolution of genome size diversity in ferns have shown that they have a distinctive genome profile compared with other land plants. Ferns are typically characterized by possessing medium‐sized genomes, although a few lineages have evolved very large genomes. Ferns are different from other vascular plant lineages as they are the only group to show evidence for a correlation between genome size and chromosome number. In this study, we aim to explore whether the evolution of fern genome sizes is not only shaped by chromosome number changes arising from polyploidy but also by constraints on the average amount of DNA per chromosome. We selected the genus Asplenium L. as a model genus to study the question because of the unique combination of a highly conserved base chromosome number and a high frequency of polyploidy. New genome size data for Asplenium taxa were combined with existing data and analyzed within a phylogenetic framework. Genome size varied substantially between diploid species, resulting in overlapping genome sizes among diploid and tetraploid spleenworts. The observed additive pattern indicates the absence of genome downsizing following polyploidy. The genome size of diploids varied non‐randomly and we found evidence for clade‐specific trends towards larger or smaller genomes. The 578‐fold range of fern genome sizes have arisen not only from repeated cycles of polyploidy but also through clade‐specific constraints governing accumulation and/or elimination of DNA.
Journal title
Journal of Systematics and Evolution
Volume
57
Issue
4
Publisher
Wiley
ISSN
1674-4918
eISSN
1759-6831