AGB-0036
QUESTION
Ideal place for insertion of DNA insert into a plasmid with two marker sites?
OPTIONS
(A) ori C
(B) Place outside the markers
(C) Inside one marker
(D) Inside both markers
ANSWER
(C) Inside one marker
EXPLANATION
When a plasmid contains two selectable marker sites, inserting the foreign DNA within one marker can disrupt that marker and provides a convenient method for identifying recombinant clones by insertional inactivation. The origin of replication is needed for plasmid replication, whereas inserting the DNA outside the markers or simultaneously inside both markers does not provide the intended marker-disruption strategy.