The genomic architecture of allopatric species is a mosaic of many conserved genes and a few adaptive ones, reflecting balance between conservation of ancestral functions and evolution of new features.
The mosses and angiosperms have independently evolved mechanisms that use the same hormones-auxin, cytokinin and strigolactone-to regulate lateral shoot branching.
Genetic analyses reveal that the TIR1/AFB auxin receptors have broadly overlapping functions throughout plant development, but that the AFB1 receptor has a specialized role in a rapid auxin response.
The system that controls gene expression by the plant signaling molecule auxin has deep evolutionary roots, and stepwise increases in system complexity shaped the highly diverse auxin response in land plants.
Transgenic analysis reveals a role for LEAFY in ferns that supports a trajectory from general to floral meristem-specific function as land plants evolved.