University of Potsdam University of Potsdam, Institute for Biochemistry and Biology Potsdam, Brandenburg, Germany
Body of Abstract: The initial redundancy between duplicated genes is thought to be resolved ultimately by subfunctionalization, neofunctionalization or pseudogenization of one of the copies. However, the molecular basis of these routes to resolving redundancy has rarely been unraveled. The BLADE-ON-PETIOLE,BOP1 and BOP2 genes arose as a result of the α whole-genome duplication about 45-50 million years ago and have been maintained as almost fully redundant duplicated copies in the lineage leading to Arabidopsis and Capsella. However, in C. rubella this redundancy has been lost with respect to bract suppression, as indicated by the fully penetrant formation of ectopic bracts in the crbop2 single mutant. Here, we report that the differential redundancy between BOP1 and BOP2 in A. thaliana versus C. rubella is based on multiple cis-regulatory changes in CrBOP1. Together these abolish CrBOP1 expression in the region of the cryptic bract, leaving only CrBOP2 active there. Thus, our findings suggest that the resolution of redundancy may be a complex, multi-step process.