A polynucleotide repeat expansion causing temperature-sensitivity persists in wild Irish accessions of Arabidopsis thaliana

Amanda Tabib, Sailaja Vishwanathan, Andrei Seleznev, Peter C. McKeown, Tim Downing, Craig Ian Dent, Eduardo Sanchez Bermejo, Luana Colling, Charles Spillane, Sureshkumar Balasubramanian

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6 Citations (Scopus)


Triplet repeat expansions underlie several human genetic diseases such as Huntington's disease and Friedreich's ataxia. Although such mutations are primarily known from humans, a triplet expansion associated genetic defect has also been reported at the IIL1 locus in the Bur-0 accession of the model plant Arabidopsis thaliana. The IIL1 triplet expansion is an example of cryptic genetic variation as its phenotypic effects are seen only under genetic or environmental perturbation, with high temperatures resulting in a growth defect. Here we demonstrate that the IIL1 triplet expansion associated growth defect is not a general stress response and is specific to particular environmental perturbations. We also confirm and map genetic modifiers that suppress the effect of IIL1 triplet repeat expansion. By collecting and analyzing accessions from the island of Ireland, we recover the repeat expansion in wild populations suggesting that the repeat expansion has persisted at least 60 years in Ireland. Through genome-wide genotyping, we show that the repeat expansion is present in diverse Irish populations. Our findings indicate that even deleterious alleles can persist in populations if their effect is conditional. Our study demonstrates that analysis of groups of wild populations is a powerful tool for understanding the dynamics of cryptic genetic variation.
Original languageEnglish
Article number1311
Pages (from-to)1-11
Number of pages11
JournalFrontiers in Plant Science
Publication statusPublished - 31 Aug 2016


  • triplet expansion
  • cryptic genetic variation
  • natural variation
  • ambient temperatre
  • QTL analysis
  • genetic modifier
  • polynucleotide repeat

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