Question

Q8. Five bacterial strains with their genotypes are listed in the table below. Res gene encode for restriction endonuclease and Mod* gene encodes for methylase. How would these strains affect the stability of their chromosomes and the cloned gene on a plasmid? (10 points) Strain E. Coli Chromosome Cloned rene on the plasmid E. coli WT E. coli (Res moda) E. coli (Res mod") E. coli (Res mod) E. coli (Res mod) І

Answer 1

If restriction endonuclease is present then the cloned gene in the plasmid will not be able to express itself as the restriction endonuclease will chop that plasmid. If the methylase enzyme is present then it will make the plasmid an easy target for the restriction endonuclease and also the chromosome will always be active. Based on this the table is as follows:

Strain	E.coli chromosome	Cloned gene in the plasmid
Wild type ecoli	normal expression levels	normal
Res-mod+	high expression	susceptible for restriction endonuclease but normal
Res-mod+	high expression	normal
Res+mod-	normal	plasmid will be cut
Res-mod-	normal	normal

If you have any query kindly comment before giving thumbs up. Thank you.