CYCLOIDEA paralogs function partially redundantly to specify dorsal flower development in Mimulus lewisii.

Premise: Duplicated genes (paralogs) are abundant in plant genomes, and their retention may influence the function of genetic programs and contribute to evolutionary novelty. How gene duplication affects genetic modules and what forces contribute to paralog retention are outstanding questions. The CYCLOIDEA(CYC)-dependent flower symmetry program is a model for understanding the evolution of gene duplication, providing multiple examples of paralog partitioning and novelty.

A few essential genetic loci distinguish Penstemon species with flowers adapted to pollination by bees or hummingbirds.

In the formation of species, adaptation by natural selection generates distinct combinations of traits that function well together. The maintenance of adaptive trait combinations in the face of gene flow depends on the strength and nature of selection acting on the underlying genetic loci. Floral pollination syndromes exemplify the evolution of trait combinations adaptive for particular pollinators.

drives delayed flowering in grown and selected at elevated CO .

Altered flowering time at elevated [CO ] is well documented, although mechanisms are not well understood. An genotype previously selected for high fitness at elevated [CO ] (SG) showed delayed flowering and larger size at flowering when grown at elevated (700 ppm) versus current (380 ppm) [CO ]. This response was correlated with prolonged expression of ( ), a vernalization-responsive floral repressor gene.

A CYC-RAD-DIV-DRIF interaction likely pre-dates the origin of floral monosymmetry in Lamiales.

Background: An outstanding question in evolutionary biology is how genetic interactions defining novel traits evolve. They may evolve either by de novo assembly of previously non-interacting genes or by en bloc co-option of interactions from other functions. We tested these hypotheses in the context of a novel phenotype-Lamiales flower monosymmetry-defined by a developmental program that relies on regulatory interaction among CYCLOIDEA, RADIALIS, DIVARICATA, and DRIF gene products.