Figure 5.

Relative Ks dating of the WGD in rice and barley-rice species divergence. Analysis of the Ks distribution among homologous gene pairs of the 10 largest duplicated segments (>10 Mb) in rice indicated the common origin of most segmental duplications (solid black color, based on Ks ratios of 1165 gene pairs) in a WGD and a more recent origin of the first duplicated segment between rice Os11 and Os12 (dashed black color, 244 gene pairs). The Ks distribution of barley-rice orthologous gene pairs (red, 816 gene pairs) suggested that WGD, although not directly detectable in barley, occurred in the common ancestor of both species, whereas gene homologs located at the ends of Os11 and Os12 together with local rice gene duplications (grey, 2433 gene pairs) were likely rice specific. The distribution of Ks ratios of paralogous barley-rice homologs (second-best non-locally duplicated rice homologs) among the identified seven ancestral duplicated segments is shown in blue (179 gene pairs).