Non-specific protein-DNA interactions and WGD.

A) Original diploid cell. Blue lines: chromosomes, green segments on the chromosomes: TF-encoding gene, yellow chromosomal segments: specific TF target binding sites, green triangles: TF protein. B) Cell after WGD. The cell volume has doubled and the concentrations of bound sites in the tetraploid (specifically or non-specifically) are the same as in the original cell. C) Cell after WGD+DNA deletions. Duplicated ‘superfluous’ DNA is removed leading to a volume shrinkage. This leads to doubling the concentration of TF-sDNA (specific interactions) with respect to the original autopolyploid or tetraploid. D) WGD+generation of junk/selfish DNA that replaces deleted DNA (red lines). Duplicated chromosomes are differentiated (diploidization) and cell volume is similar to that of the original tetraploid and the concentrations TF-sDNA and TF-nsDNA are respected.