Abstract: The invention relates to a process for the rescue and cloning of a DNA sequence wherein a vector containing said DNA sequence is multiplied in a suitable bacterial host. As the bacterial host, a bacterial strain which is incapable of host restriction is used, such as an Escherichia coli C strain. Preferably, a bacteriophage vector which is a suitable cloning vehicle for the bacterial host concerned is used as the vector, the step of in vitro packaging into phage coats being performed by means of a phage packaging extract obtained from a bacterial strain which is incapable of host restriction.