Thermo Scientific™ Lambda DNA is a temperate E. coli bacteriophage.

Applications:
Activity and specificity assays of restriction enzymes
Preparation of DNA molecular weight standards
Cloning

The virion DNA is linear and double-stranded (48502 nt) with 12 bp single-stranded complementary 5’-ends. After the phage particle injects its chromosome into the cell, the chromosome circularises by end joining. In the lytic pathway, phage genes encoding replication, lysis and virion proteins are expressed. The chromosome replicates and the replicas are cleaved and packaged into progeny phage particles. In the lysogenic pathway phage gene expression is repressed and the circular chromosome inserts into the bacterial chromosome by recombination.

Phage lambda DNA is a common substrate for restriction endonucleases and for generating DNA size marker fragments. For large scale isolation of phage DNA, cI857Sam7, a mutant carrying four known mutations, is used. The DNA sequence used to construct a phage alpha restriction map includes these mutations.