The molecular machinery that starts the process by which a biological cell divides into two identical daughter cells apparently worked so well early on that evolution has conserved it across the eons in all forms of life on Earth. Researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the University of California at Berkeley have shown that the core machinery for initiating DNA replication is the same for all three domains of life — Archaea, Bacteria and Eukarya.
Given that, according to Carl Woese, the three domains are not descended from a common ancestor (see here), is it plausible that this same switch could have arisen apart from design three times?