The A sub genomes of eight rape accesions were aligned to C sub genomes using Mummer (version 3.23) with parameters settings ‘-g 1000 -c 90 -l 40’. The alignment block was then filtered out of the mapping noise and the one-to-one alignment was identified by delta-filter with parameters settings ‘-r -q’.You can download the detail of syntenic links here and the statistics of homologous regions in eight rape genomes are as follows.