Does expression divergence of the AGL6 MADS domain transcription factor lineage after a core eudicot duplication suggest functional diversification?
These and previous data lead us to propose that the AGL6 lineage in core eudicots, in addition to functions related to the expression in reproductive structures, may have acquired a function in developmental transitions of vegetative shoots.
Along with previous studies indicating intron-rich genes with weak intron boundary consensus and complex spliceosomes in ancestral organisms, our results suggest that at least a simple form of alternative splicing may already have been present in the unicellular ancestor of plants, fungi and animals. A role for alternative splicing in the evolution of multicellularity then would largely have arisen by co-opting the preexisting process.