1.) How is PCR superior to colony hybridization for identifying DNA sequences of interest? 2.) What is the natural function of bacterial restriction endonucleases? How might the presence of...

1

1.) How is PCR superior to colony hybridization for identifying DNA sequences of interest?
Ans. Colony Hybridization is a technique in which radio-labelled gene probes are made to attach to
complementary base sequences to identify a gene of interest. In this technique, the bacterial
colonies are first transferred to a nitrocellulose membrane and then the cells are lysed and DNA is
denatured with the help of NaOH. The strands are then fixed on the filter and made to hybridize
with complementary radioactive labelled probes. Finally, colonies containing desired gene are
identified using autoradiography. Polymerase Chain reaction (PCR) enables the rapid synthesis of
large number of copies of a specific DNA fragment from a complex mixture of DNA. Researchers can
thus obtain large quantities of specific pieces of DNA for experimental and diagnostic purposes.
Thus, this is why PCR is superior to colony Hybridization because it is easier and also amplifies a DNA
fragment to obtain large copies of those fragments.
2.) What is the natural function of bacterial restriction endonucleases? How might the presence of
restriction enzymes affect the use of bacteria as hosts...