Like in Cluster A and BD phages, the DNA primase of many cluster BF phages is split into two overlapping reading frames. The upstream portion of the gene may be missed by Glimmer and Genemark and may not be called in DNA Master.

As per the entries in Cluster A and BD: "We are not sure what happens within the cell during the infection to generate the correct full length primase, so for now, we add both parts to the annotations with a large overlap."