The post-fertilization archegonium gene network of seedless plants contributed to the origin of seeds (opens in new tab)

The evolution of seeds was a critical transition in plant evolution, but how ancestral seedless development was modified to form the first seed is only partly-answered through comparative morphology or the fossil record. We investigate seed origins by quantifying gene network conservation between seeds and seedless plant reproductive organs. Characterizing reproduction in the homosporous fern Ceratopteris richardii as a proxy for ancestral seedless reproduction, we create a gene expression at...