Cytogenetic relationships of six cultivated Brassica species as depicted by U's triangle . U's triangle illustrates the evolutionary relationship between three cultivated elementary species (B. rapa, B. oleracea, and B. nigra) and three amphiploid species (B. napus, B. juncea, and B. carinata). Chromosome numbers, nuclear genome types and mitotypes are shown inside or outside the circle for each species.
Chang et al. BMC Genomics 2011 12:497 doi:10.1186/1471-2164-12-497