Genetica

, Volume 115, Issue 1, pp 37–47

Feast and famine in plant genomes

Authors

  • Jonathan F. Wendel
    • Department of BotanyIowa State University
  • Richard C. Cronn
    • Department of BotanyIowa State University
  • J. Spencer Johnston
    • Department of EntomologyTexas A & M University
  • H. James Price
    • Department of Soil and Crop SciencesTexas A & M University
Article

DOI: 10.1023/A:1016020030189

Cite this article as:
Wendel, J.F., Cronn, R.C., Spencer Johnston, J. et al. Genetica (2002) 115: 37. doi:10.1023/A:1016020030189

Abstract

Plant genomes vary over several orders of magnitude in size, even among closely related species, yet the origin, genesis and significance of this variation are not clear. Because DNA content varies over a sevenfold range among diploid species in the cotton genus (Gossypium) and its allies, this group offers opportunities for exploring patterns and mechanisms of genome size evolution. For example, the question has been raised whether plant genomes have a ‘one-way ticket to genomic obesity’, as a consequence of retroelement accumulation. Few empirical studies directly address this possibility, although it is consistent with recent insights gleaned from evolutionary genomic investigations. We used a phylogenetic approach to evaluate the directionality of genome size evolution among Gossypium species and their relatives in the cotton tribe (Gossypieae, Malvaceae). Our results suggest that both DNA content increase and decrease have occurred repeatedly during evolution. In contrast to a model of unidirectional genome size change, the frequency of inferred genome size contraction exceeded that of expansion. In conjunction with other evidence, this finding highlights the dynamic nature of plant genome size evolution, and suggests that poorly understood genomic contraction mechanisms operate on a more extensive scale that previously recognized. Moreover, the research sets the stage for fine-scale analysis of the evolutionary dynamics and directionality of change for the full spectrum of genomic constituents.

cotton DNA content genome evolution genome size Gossypium Malvaceae molecular evolution 2C values

Copyright information

© Kluwer Academic Publishers 2002