Table 2.

Summary of main orthologous and paralogous relationships among Ae. tauschii, rice, and sorghum chromosomes or their sections

Ae. tauschiiRiceSorghum
1D (3D + 4D)Os5 (Os1) + Os10 (Os3)Sb9 (Sb3) + Sb1 (Sb1)
2D (6D + 4D)Os4 (Os2) + Os7 (Os3)Sb6 (Sb4) + Sb2 (Sb1)
3D (1D)Os1 (Os5)Sb3 (Sb9)
4D (1D + 5D)Os3 (Os7 + Os10) + Os11 (Os12)Sb1 (Sb2 + Sb1) + Sb5 (?)
5D (4D + 7D+?)Os12 (Os11)+ Os9 (Os8) + Os3 (?)Sb8 (Sb5) + Sb2 (Sb7) + Sb1 (?)
6D (7D + 2D)Os2 (Os6 + Os4)Sb4 (Sb10 + Sb6)
7D (6D + 5D + 4D)Os6 (Os2) + Os8 (Os9) + Os3 (?)Sb10 (Sb4) +Sb7 (Sb2) + Sb1 (?)
  • Across each row, chromosomes in bold are orthologous to complete chromosomes or their sections but paralogous to chromosomes or their sections in parentheses. Chromosomes in parentheses are orthologous across species but paralogous to those in bold. For instance, chromosome 1D consists of two sections orthologous to Os5 and Os10 and Sb9 and Sb1; Os5 is orthologous to Sb9 and Os10 to Sb1. The two 1D sections are paralogous to sections of 3D and 4D, Os1 and Os3 and Sb3 and Sb1. The section of 3D is orthologous to sections of Os1 and Sb3 and the section of 4D is orthologous to sections of Os3 and Sb1. Chromosome Sb1 is paralogous to itself, which is caused by the fusion of orthologues of Os10 with Os3 in the sorghum genome, making up Sb1. In the chromosome 4D row, chromosomes Os7 and Os10 and sections of Sb2 and Sb1 are paralogous to Os3 and Sb1. The results imply that a section of Os7 is orthologous to 1D, for which there is no evidence. The anomaly is caused by the paralogous relationship of a section of 1D to a section of Os3 which, in turn, is paralogous to two chromosomes, Os7 and Os10, within the rice genome (20).