Phage lambda is one of the key model organisms on which molecular biology was built. Such a wealth of existing knowledge on this organism makes it an ideal test model for systems biology. In this article in Microbiology Today (pdf) Rosalind Allen explores the usefulness of this bacteriophage to systems biology and vice versa:
Phage lambda, discovered in 1950, infects sensitive strains of E. coli. For a genome of only 48.5kb, packed into a particle of only 50nm diameter, this phage has attracted a lot of attention. Phage lambda became one of the key model organisms on which modern molecular biology was built. Over a period of intense study lasting 40 years, the genes in the phage lambda genome, the proteins encoded by them and the interactions between these genes and proteins were investigated in great detail. The humble phage lambda was the source of discoveries such as repression and activation mechanisms for gene regulation, chaperone proteins, DNA recombination and restriction enzymes, which microbiologists and many others now take for granted. This huge body of knowledge makes it the ideal test case for systems biology modelling.