Highly expressed genes are preferentially co-opted for new functions during the emergence of C4 photosynthesis

Our work uses comparative transcriptomics to identify the factors that increase the likelihood of genes being co-opted for novel metabolic pathways. We sequenced 19 grass species, representing both C4 and non-C4 phenotypes. Through modeling, we show that genes that were the most highly expressed in the leaves of the non-C4 ancestors were preferentially co-opted for the C4 physiology, independently of their tissue specificity.