Wheat paleohistory created asymmetrical genomic evolution

- Modern plants are diploidized paleopolyploids shaped through subgenome dominance.
- Subgenome dominance derives more fractionated and less fractionated compartments.
- Rosids, Brassiceae, wheat derive from polyploid progenitors of 7-14-21-chromosomes.
- Wheat paleopolyploidy and neopolyploidy derive organization and regulation subgenome asymmetry.

Following the triplication reported in Brassiceae ∼10 million years ago, and at the basis of rosids ∼100 million years ago, bias in organization and regulation, known as subgenome dominance, has been reported between the three post-polyploidy compartments referenced to as less fractionated (LF), medium fractionated (MF1) and more fractionated (MF2), that have been proposed to derive from an hexaploidization event involving ancestors of 7-14-21 chromosomes. Modern bread wheat experienced similar paleohistory during the last half million year of evolution opening a new hypothesis where the wheat genome is at the earliest stages on the road of diploidization through subgenome dominance driving asymmetry in gene content, gene expression abundance, transposable element content as dynamics and epigenetic control between the A, B and D subgenomes.