How Plants Sort and Eliminate Genes Over Millennia.

Hybrid plants with multiple genome copies show evidence of preferential treatment of the genes from one ancient parent over the genes of the other parent, even to the point where some of the unfavored genes eventually are deleted. Previous work has shown that plant genomes with historical duplications from tens of millions of years ago have lost one of the two copies in large blocks along the chromosome, consistent with the preferential loss of one parent's contribution. The discovery of this may show a new  path of evolutionary plant biology.  The team also found that gene pairs that are co-expressed in similar tissues are preferentially expressed from the same parent. Even in the rare cases when an Arabidopsis thaliana gene was more abundantly expressed in the hybrid, co-expressed genes would also be preferentially expressed from the Arabidopsis thaliana copy.