Mutator Strain Lab Report

Introduction A mutator strain is one that lacks certain repair methods when a mistake is made during DNA replication. The strain of E. coli that was used in this lab, XL-1 Red Mutator, lacked three different repair methods used to correct mistake in DNA replication. If a mistake occurred, the E. coli would not be able to make repairs via DNA polymerase backtracking, mismatch repair, or oxo-dGTP hydrolysis. The E. coli will still be able to use the other ways to repair mistakes including SOS repair. The result is that the XL-1 Red Mutator strand has a thousand more mistakes than an E. coli strand that has all its repair options. This allows mutations to occur at a much higher rate during DNA replication and good for research. Introduction of the pGLO, which glows fluorescent under UV light, helps
If a growing colony is dark under UV light, a mutation has occurred.

Methods E. coli mutator was transformed with pGLO. A broth was inoculated and serial passaging was performed for seven days. A kit was then used for DNA purification. Competent cells were mixed with the DNA samples in an ice bath. Tubes were kept in the ice bath for 30 minutes. The tubes were then heat shocked at 42℃ for 90 seconds. The tubes were then returned to the ice bath for one minute. 1 ml of LB broth was added to each tube for outgrowth and placed in an incubator set at 37℃ for 45 minutes. The cells were then spread on a grow plate of LB-amp-arabinose and placed in an incubator at 37℃ overnight. Colonies were then checked with a UV light to look for green glow. If a colony was dark, then it was a