Biology dictionary

Lambda bacteriophage

(Science: virology) bacterial dna virus, first isolated from E. Coli. Its structure is similar to that of the t even phages.

lambda genetic material consists of a double-stranded dna molecule with 5' twelve-base-pair sticky ends, known as cos sites, which permit circularisation of the dna molecule. It shows a lytic cycle and a lysogenic cycle and studies on the control of these alternative cycles have been very important for our understanding of the regulation of gene transcription.

It is used as a cloning vector, accommodating fragments of dna up to 15 kilobase pairs long. For larger pieces, the cosmid vector was constructed from its ends.