The prophage expresses gene(s) that repress the phage's lytic action, until this repression is disrupted (see lytic cycle).
Currently a variety of studies are being conducted to see whether other genes are active during lysogeny, examples of which include phage-encoded tRNA and virulence genes.
Theories about Lysogeny dominated the field of microbiology between 1920 and 1929.
[1] Lysogenic conversion is a process that occurs between a bacterium and a phage that is often beneficial for the bacteria.
In lysogenic conversion, the phage inserts specific characteristics into the bacterial genes causing the bacteria to have better survival.