Shown below is a cloning vector 'Z' that Kamla wants to use to create a recombinant vector with her gene of interest.
The vector consists of sites for three restriction enzymes - ScaI, HindIII and EcoRI. Restriction sites for the same enzymes are also present in the gene of interest. There are two 'ori' sequences - one allows it to replicate in Escherichia coli and another allows replication in Zymomonas mobilis. Apart from this, the vector consists of two antibiotic resistance genes - one against tetracycline (tet) and another against chloramphenicol (cml).
(a) What is the advantage of having two 'ori' sequences in the same vector? Give a situation in which this would be particularly useful.