It is now well established that the remarkably complex eukaryotic DNA replication apparatus evolved from a related but simpler machinery found in present day archaea. However, the evolutionary events that underpin the duplication and diversification of replication factors have been enigmatic. A new study of the DNA replication machinery of Asgard archaea, just published in Nature Ecology and Evolution arising from a collaboration between Steve Bell’s lab and that of Professor Fabai Wu in the Eastern Institute of Technology, Ningbo, China has shed light on some of these key transitional events.