I isolate the entire genome of the bacteria E. coli. I then digest the genome wi
ID: 81679 • Letter: I
Question
I isolate the entire genome of the bacteria E. coli. I then digest the genome with a restriction enzyme. I then ligate the digested fragments with the Ampicillin-resistance gene. Following digestion, I select for all the successfully ligated and circularized products, and then use these to transform E. coli. I plate the transformed cells on Ampicillin-containing media, and get some colonies.
a) What specific sequence from the E. coli genome MUST be present in plasmids that produce colonies on the Ampicillin-containing plates? Explain your answer.
b) MOST LIKELY what might have been the purpose of this experiment? Explain.
Explanation / Answer
In this question one more possibility is that some fragment will incorporate into the host genome and they will multiply with cells (by homologous recombination). Probability is very less. For this ampicillin gene should be present between two genes which are adjacent in E. coli genome and in restriction fragments ampicillin is present in between these genes. ( gene 1-gen2 in E.coli genome and Gene 1-amp- Gene 2 in restriction fragment)
As mentioned in first part that probably isolation of origin of replication DNA sequence of E. coli