Ancestral grass karyotype reconstruction unravels new mechanisms of genome shuffling as a source of plant evolution

Model for grass chromosome evolution and shuffling. The model begins with WGD (A), followed by centromeric breaks (B) or terminal breaks (C), interchromosomal break repair (D), and intra-CBR mechanisms (E, F), respectively, between nonhomologous (A) and homologous chromosomes (E) to explain the observed NCF and CI pattern (G) as well as repeat/TE, gene, and CO distribution in rice, maize, sorghum, and Brachypodium genomes, resulting from their paleo-history from their common AGK (H). Colored arrows represent the different alternative orientation of the double-strand break repair to explain the actual syntenic chromosome order and orientation observed among rice, Brachypodium, sorghum, maize.