Polyploidy is a key force in the evolution of flowering plants. Allopolyploidy involves a merge of distanc
genomes followed by whole-genome duplication. Recently formed allopolyploids retain duplicated
copies of most genes on homoeologous chromosomes. However, it appears that the contribution of
parentel genomes need not to be equal and that altered gene expression is common. Such a divergence is
believed to develop in two phases. The first takes place immediately after the hybrid formation, the
second is a gradual evolution of gene expression mediated by diversification of duplicated genes.
