Genome size variation at constant chromosome number is not correlated with repetitive DNA dynamism in Anacyclus (Asteraceae)
Resource type
Journal article
Creator (person)
Vitales, Daniel
Álvarez, Inés
Garcia, Sònia
Hidalgo, Oriane
Nieto Feliner, Gonzalo
Pellicer, Jaume
Vallès, Joan
Garnatje, Teresa
Date published
November 7, 2019
Abstract
Abstract
Background and Aims
Changes in the amount of repetitive DNA (dispersed and tandem repeats) are considered the main contributors to genome size variation across plant species in the absence of polyploidy. However, the study of repeatome dynamism in groups showing contrasting genomic features and complex evolutionary histories is needed to determine whether other processes underlying genome size variation may have been overlooked. The main aim here was to elucidate which mechanism best explains genome size evolution in Anacyclus (Asteraceae).
Methods
Using data from Illumina sequencing, we analysed the repetitive DNA in all species of Anacyclus, a genus with a reticulate evolutionary history, which displays significant genome size and karyotype diversity albeit presenting a stable chromosome number.
Key Results
By reconstructing ancestral genome size values, we inferred independent episodes of genome size expansions and contractions during the evolution of the genus. However, analysis of the repeatome revealed a similar DNA repeat composition across species, both qualitative and quantitative. Using comparative methods to study repeatome dynamics in the genus, we found no evidence for repeat activity causing genome size variation among species.
Conclusions
Our results, combined with previous cytogenetic data, suggest that genome size differences in Anacyclus are probably related to chromosome rearrangements involving losses or gains of chromosome fragments, possibly associated with homoploid hybridization. These could represent balanced rearrangements that do not disrupt gene dosage in merged genomes, for example via chromosome segment exchanges.
Journal title
Annals of Botany
Volume
125
Issue
4
Publisher
Oxford University Press (OUP)
ISSN
0305-7364
eISSN
1095-8290
Keywords