Genome size expansion and the relationship between nuclear DNA content and spore size in the Asplenium monanthes fern complex (Aspleniaceae)

BMC Plant Biology

Research Article

Robert J Dyer¹  Harald Schneider²  Vincent Savolainen³  Jaume Pellicer⁴  Ilia J Leitch⁴ 

[1] Department of Botany, Natural History Museum, SW7 5BD, London, UK;Imperial College London, Silwood Park Campus, SL5 7PY, Ascot, Berkshire, UK;Centre for Ecology and Hydrology, OX10 8BB, Wallingford, Oxfordshire, UK;Department of Botany, Natural History Museum, SW7 5BD, London, UK;State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, China;Imperial College London, Silwood Park Campus, SL5 7PY, Ascot, Berkshire, UK;Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3AB, Richmond, Surrey, UK;Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3AB, Richmond, Surrey, UK;

关键词: Genome size;    Chromosome size;    DNA content;    C-value;    Monoploid;    Holoploid;    Polyploidy;    Asplenium monanthes;    Apomixis;    Spore size;   

DOI  :  10.1186/1471-2229-13-219

 received in 2013-09-11, accepted in 2013-12-10,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundHomosporous ferns are distinctive amongst the land plant lineages for their high chromosome numbers and enigmatic genomes. Genome size measurements are an under exploited tool in homosporous ferns and show great potential to provide an overview of the mechanisms that define genome evolution in these ferns. The aim of this study is to investigate the evolution of genome size and the relationship between genome size and spore size within the apomictic Asplenium monanthes fern complex and related lineages.ResultsComparative analyses to test for a relationship between spore size and genome size show that they are not correlated. The data do however provide evidence for marked genome size variation between species in this group. These results indicate that Asplenium monanthes has undergone a two-fold expansion in genome size.ConclusionsOur findings challenge the widely held assumption that spore size can be used to infer ploidy levels within apomictic fern complexes. We argue that the observed genome size variation is likely to have arisen via increases in both chromosome number due to polyploidy and chromosome size due to amplification of repetitive DNA (e.g. transposable elements, especially retrotransposons). However, to date the latter has not been considered to be an important process of genome evolution within homosporous ferns. We infer that genome evolution, at least in some homosporous fern lineages, is a more dynamic process than existing studies would suggest.

【 授权许可】

CC BY   
© Dyer et al.; licensee BioMed Central Ltd. 2013