Rapid, repeated, and clustered loss of duplicate genes in allopolyploid plant populations of independent origin

Curr Biol. 2012 Feb 7;22(3):248-52. doi: 10.1016/j.cub.2011.12.027. Epub 2012 Jan 19.


The predictability of evolution is debatable, with recent evidence suggesting that outcomes may be constrained by gene interaction networks [1]. Whole-genome duplication (WGD; polyploidization-ubiquitous in plant evolution [2]) provides the opportunity to evaluate the predictability of genome reduction, a pervasive feature of evolution [3, 4]. Repeated patterns of genome reduction appear to have occurred via duplicated gene (homeolog) loss in divergent species following ancient WGD [5-9], with evidence for preferential retention of duplicates in certain gene classes [8-10]. The speed at which these patterns arise is unknown. We examined presence/absence of 70 homeologous loci in 59 Tragopogon miscellus plants from five natural populations of independent origin; this allotetraploid arose ~80 years ago via hybridization between diploid parents and WGD [11]. Genes were repeatedly retained or lost in clusters, and the gene ontology categories of the missing genes correspond to those lost after ancient WGD in the same family (Asteraceae; sunflower family) [6] and with gene dosage sensitivity [8]. These results provide evidence that the outcomes of WGD are predictable, even in 40 generations, perhaps due to the connectivity of gene products [8, 10, 12]. The high frequency of single-allele losses detected and low frequency of changes fixed within populations provide evidence for ongoing evolution.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Evolution, Molecular*
  • Gene Deletion*
  • Gene Duplication*
  • Genome, Plant
  • Polyploidy*
  • Tragopogon / genetics*