A molecular update on the origin of the carpel.

Carpels, the female reproductive organs of flowering plants, are of major economic importance since much of our food is ultimately derived from carpel tissue and they are a defining innovation for flowering plants. Amazingly, little is known about the origin and conservation of the developmental program of the carpel besides the knowledge generated by utilizing Arabidopsis thaliana. However, in the past few years advances in ancestral state reconstruction, developmental genetics, and phylogenetic analyses led to advances in the field of flower evodevo. Here, I summarize recent work on ancestral state reconstructions of carpels, and the functions of the major components of the genetic networks governing carpel development described for Arabidopsis. Then, I point out how the stepwise addition of genes during land plant evolution has generated the A. thaliana carpel's developmental toolkit. By merging these observations, I propose a basic version of the ancestral angiosperm carpel developmental network.