Insights into the Common Ancestor of Cereals

Abstract Their economic and agricultural importance has motivated whole-genome sequencing efforts of a diverse sampling of cereals, facilitating new research to understand the evolution of their common ancestor. Our analyses of the genome sequences of rice, sorghum, maize, and a non-cultivated pooid, Brachypodium , have revealed the occurrence of polyploidizations, genome structural changes, illegitimate recombination between homoeologous chromosomal regions, biological pathway evolution, evolution of gene repertoire, and other important dimensions of evolution in cereal common ancestor(s) after and even before a whole-genome duplication occurring tens of million years ago in a common ancestor of all these plants. One pair of grass chromosomes duplicated in this event has been greatly affected by illegitimate recombination, facilitating ongoing gene conversion and resulting in a stratification of divergence patterns along their length from the centromeres to the telomeres. These findings will possibly help to decipher mysteries regarding the ecological and agricultural success of cereals and other members of the grass family. Increasing fundamental knowledge of the cereal common ancestor may contribute to understanding botanical diversity and applying that knowledge to sustainable improvement of crop productivity.