Which of the following is known as the natural genetic engineer?

The enzyme known as restriction endonuclease:

An enzyme catalysing the removal of nucleotides from the ends of $DNA$ is:

The characteristics of a molecular probe are
$I.$ very long molecule
$II.$ double-stranded
$III.$ $DNA$ or $RNA$
$IV.$ complementary to a part of the desired gene
The correct pair is

$EcoRI$ derives from ..........

$A$ : $DNA$ ligase plays an important role in recombinant $DNA$ technology.
$R$ : The linking of antibiotic resistance gene with plasmid vector became possible by enzyme $DNA$ ligase.