Differentiation of the maize subgenomes by genome dominance and both ancient and ongoing gene loss

Ancient tetraploidies are found throughout the eukaryotes. After duplication, one copy of each duplicate gene pair tends to be lost (fractionate). For all studied tetraploidies, the loss of duplicated genes, known as homeologs, homoeologs, ohnologs, or syntenic paralogs, is uneven between duplicate regions. In maize, a species that experienced a tetraploidy 5-12 million years ago, we show that in addition to uneven ancient gene loss, the two complete genomes contained within maize are differentiated by ongoing fractionation among diverse inbreds as well as by a pattern of overexpression of genes from the genome that has experienced less gene loss. These expression differences are consistent over a range of…

• NS
  National Science Foundation