Fig. 1

Chromosome fusions during the evolution of Hordeum vulgare and Aegilops tauschii. Chromosomes, shown as rectangular blocks, are arranged horizontally and vertically to the dot-plot. The color scheme (A1-A7, the seven ancestral chromosomes was used seven different colors as reference were related to chromosomes in different grasses) for the chromosomes of grasses follows that of a previous study [19]. Homologous blocks can be classified as primary, resulting from chromosomal orthology, and secondary, resulting from paralogy from ancestral polyploidy. Hv, Hordeum vulgare; Ae, Aegilops tauschii; Os, Oryza sativa. a Formation of chromosome Hv1; b formation of chromosome Hv2; c formation of chromosome Hv7; d formation of chromosome Hv4 and Hv5; e formation of chromosome Ae1; f formation of chromosome Ae2; g formation of chromosome Ae7; h formation of chromosome Ae4 and Ae5