The following diagram showing restriction sites in $E$. coli cloning vector pBR322. Find the role of ' $X$ ' and ' $Y$ genes:

$I.$ Bacteriophages are $…A…$ infecting $…B….$

$II. …C…$ are hybrid vectors derived from plasmids which contain or site of $\lambda$ phage

$A, B$ and $C$ in above statements refers to

Which of the following statement is not correct about cloning vector ?

In gel electrophoresis, the separated bands of $DNA$ are cut out and extracted from the gel piece. This step is called

Although the $Ti $ plasmid has revolutionised plant genetic engineering one limitation of its use is that it