| Comments |
P.8583 right column bottom paragraph: "To indicate their diverse indispensable contributions to the phenotype, [investigators] enumerate core processes in Table 1, associating each with one of four major episodes of pre-Cambrian functional innovation (mostly protein evolution). These biochemical, molecular genetic, cell biological, physiological, and developmental components (which fill the textbooks of these fields) were carried forward, unchanged, in all bilateral animals. This, [they] argue, was such a powerful and versatile toolkit that post-Cambrian animals could largely omit further functional innovation at the gene product level (protein and functional RNA evolution) and instead exploit regulatory innovation to diversify anatomy, physiology, and development. What is remarkable about the processes, as a large set, is that they can be used in so many contexts toward so many ends. They define the envelope of possibilities of what regulatory change can achieve." |