Before revision:  This transition was facilitated by an emergent gene repertoire devoted to developmental regulation, which involved gene family expansion and diversification as well as gene innovation. Unknown, however, is whether the loss of key genes co-evolved with and/or facilitated this genomic rewiring .
After revision:  This transition was facilitated by an emergent gene repertoire for gastrulation. Whether loss of genes also co-evolved with and/or facilitated this genomic rewiring .