Tentative scenarios of the origin of nine Pachycladon chromosomes (PC1- PC6, PC8-PC10) from the duplicated Ancestral Crucifer Karyotype (ACK). Duplicated 24 conserved genomic blocks (A-X) of the ACK are colored according to their position on chromosomes AK1 to AK8 . Blocks split into two parts are labeled as „a" and „b". Centromeres of Pachycladon chromosomes are depicted as sandglass-like structures colored according to their presumed origin from AK chromosomes. Inactivated and/or lost ancestral centromeres are shown outside the modern Pachycladon chromosomes. Downward-pointing arrows indicate the opposite orientation of genomic blocks as compared to their position within the ACK . Jagged lines mark purported breakpoints of inferred chromosome rearrangements.