λ Phase Genetic Switch

[Helics]

λ phase infect K-12 starin of E.coli, it insert it's DNA inside the E.coli cell. How the phase DNA discriminate the host genomes from plasmid DNA ? can you please help me ?

[lenni]

the λ-phage inserts his DNA by recombination; the integration is site-specific, the recognition-site is found to by 15bp long and is located between the gacactose and tryptophan genes...
My thesis: as long as the plasmid DNA doesn`t contain the recognition-sequence, the integration of the λ-DNA is restricted to the bacterial chromosome
but I am not sure; maybe it is caused by another mechanism...