Figure 1.
Definition of homologous gene quartets and inference of conversion based on phylogenetic topology changes. (A) Arrows show genes and the like-colored ones show homologous genes. Paralogous gene quartets formed by rice (R) paralogous genes R1 and R2, and their respective sorghum (S) orthologs S1 and S2. (B–E) Squares symbolize a duplication event in the common ancestral genome and circles symbolize species divergence. The expected phylogenetic relationship of the homologous quartets is displayed in (B) if no conversion has occurred; (C) if gene R2 is converted by R1; (D) if gene S1 is converted by S2; and (E) if both the above conversions occurred.
