The Flax Genome, a Revolution in Evolution

The flax genome can be rapidly modified within a single generation. The variations do not appear to be either random mutations or movement of transposable elements but rather the alternation between alternative states, that is the genome appears to be able to switch between two well defined states at many loci. The genomes of eight lines, (genotrophs) all derived from the same progenitor line (Pl), have been compared to the reference genome of the flax variety Bethune. The differences fall into two main classes. One, differences where regions of the genome have large insertions or deletions (more than 500 bp) among the genotrophs compared to Pl. Where there are insertions compared to the progenitor line, the inserted sequence is identical (or very similar) to the sequence in Bethune. A second set of differences is where Pl and the genotrophs have a large number of SNPs over a short region of the genome. Again, one of the sets of lines is the same as Bethune and the other is very different but all the altered variants are identical. Since all the alignments are to the reference Bethune, regions unique to Pl or the genotrophs have not yet been identified. An example that typifies the variation is the Linum insertion sequence-1 (LIS-1). This sequence, when transformed into Arabidopsis behaves the same way as it does in flax. Therefore, these genomic processes that make large reproducible modifications of the genome are not limited exclusively to flax but also exist in (all) other plants.