The process in which DNA-dependent DNA replication is started; this begins with the ATP dependent loading of an initiator complex onto the DNA, this is followed by DNA melting and helicase activity. In bacteria, the gene products that enable the helicase activity are loaded after the initial melting and in archaea and eukaryotes, the gene products that enable the helicase activity are inactive when they are loaded and subsequently activate. [ http://www.ncbi.nlm.nih.gov/pubmed/28209641 https://www.worldcat.org/search?q=bn%3A0815316194 https://www.worldcat.org/search?q=bn%3A071673706X ]