Species-specific double-strand break repair and genome evolution in plants

EMBO J. 2000 Oct 16;19(20):5562-6. doi: 10.1093/emboj/19.20.5562.

Abstract

Even closely related eukaryotic species may differ drastically in genome size. While insertion of retroelements represents a major source of genome enlargement, the mechanism mediating species- specific deletions is fairly obscure. We analyzed the formation of deletions during double-strand break (DSB) repair in Arabidopsis thaliana and tobacco, two dicotyledonous plant species differing >20-fold in genome size. DSBs were induced by the rare cutting restriction endonuclease I-SCE:I and deletions were identified by loss of function of a negative selectable marker gene containing an I-SCE:I site. Whereas the partial use of micro-homologies in junction formation was similar in both species, in tobacco 40% of the deletions were accompanied by insertions. No insertions could be detected in Arabidopsis , where larger deletions were more frequent, indicating a putative inverse correlation between genome size and the average length of deletions. Such a correlation has been postulated before by a theoretical study on the evolution of related insect genomes and our study now identifies a possible molecular cause for the phenomenon, indicating that species-specific differences in DSB repair might indeed influence genome evolution.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Blotting, Southern
  • DNA Repair / genetics*
  • DNA, Bacterial / genetics
  • DNA, Plant / genetics*
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Evolution, Molecular*
  • Genes, Plant / genetics
  • Genome, Plant*
  • Mutagenesis, Insertional / genetics
  • Plants, Genetically Modified
  • Plants, Toxic*
  • Promoter Regions, Genetic / genetics
  • Saccharomyces cerevisiae Proteins
  • Sequence Deletion / genetics
  • Species Specificity
  • Tobacco / genetics*
  • Transformation, Genetic
  • Transgenes / genetics

Substances

  • DNA, Bacterial
  • DNA, Plant
  • Saccharomyces cerevisiae Proteins
  • T-DNA
  • SCEI protein, S cerevisiae
  • Deoxyribonucleases, Type II Site-Specific