Arabidopsis ecotypes show a significant variation in flowering time. One of the major determinants of this character is the FRIGIDA (FRI) locus. In an article published in October 13, 2000 Science, Dr. Caroline Dean, Urban
Johanson and associates at John Innes Centre, UK with collaborators Drs. Rick Amasino and Scott Michaels of the University of Wisconsin have shown that allelic variation of this locus contributes to different flowering time in Arabidopsis. When FRI allele is dominant, it conditions late flowering. By means of vernalization1, earliness can be induced in otherwise late flowering Arabidopsis ecotypes.
The authors cloned the FRI gene in order to determine the molecular basis of the allelic variation. The results of their analysis showed that the alleles of most of the early-flowering ecotypes carry one of two different deletions disrupting the open reading frame. The altered trait from late to early flowering time has been attributed to the change of the ORF in the FRI locus.
The authors concluded that loss-of-function mutations at the FRI locus have led to the evolution of many early-flowering ecotypes.
Vernalization = the induction of flowering by cold treatment
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