Abstract

Genome size varies c. 2400-fold in angiosperms (flowering plants), although the range of genome size is skewed towards small genomes, with a mean genome size of 1C=5.7Gb. One of the most crucial factors governing genome size in angiosperms is the relative amount and activity of repetitive elements. Recently, there have been new insights into how these repeats, previously discarded as 'junk' DNA, can have a significant impact on gene space (i.e. the part of the genome comprising all the genes and gene-related DNA). Here we review these new findings and explore in what ways genome size itself plays a role in influencing how repeats impact genome dynamics and gene space, including gene expression.

Highlights

  • Large-scale comparative analyses of plant genome sizes (GS) available in the Plant DNA C-values database have shown that angiosperms are remarkable in their GS diversity. Do they have the largest range for any comparable eukaryotic group, varying c. 2400-fold (1C = 0.063–148.8 Gb), but they include the largest eukaryotic genome so far recorded3 [i.e. Paris japonica, 1] which is c. 950Â larger than the genome of Arabidopsis thaliana (1C = 0.157 Gb)

  • We propose that an understanding of gene evolution and gene regulation requires a deep understanding of the genomic context of gene space, that is, the repeat landscape and genome architecture within which a gene is embedded

  • To reduce the frequency of these processes, eukaryote genomes have evolved a variety of mechanisms to epigenetically silence repeat activity, including RNA-directed DNA methylation (RdDM; involving small interfering RNAs, siRNAs), www.sciencedirect.com

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Summary

Introduction

Large-scale comparative analyses of plant genome sizes (GS) available in the Plant DNA C-values database (www.data.kew.org/cvalues) have shown that angiosperms (flowering plants) are remarkable in their GS diversity. Do they have the largest range for any comparable eukaryotic group, varying c. Location, and diversity of repeat sequences have a significant impact on gene space evolution [9]. To reduce the frequency of these processes, eukaryote genomes have evolved a variety of mechanisms to epigenetically silence repeat activity, including RNA-directed DNA methylation (RdDM; involving small interfering RNAs, siRNAs), www.sciencedirect.com

74 Genomes and evolution
11. Lisch D
22. Grandbastien M-A
36. Freeling M
Findings
41. Fedoroff NV
Full Text
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