Question

Choose the correct statement for construction of a library subsection.

(a) The size of a particular restriction fragment on which the gene is located is not known

(b) The size of the restriction fragment can be known by carrying out southern blotting

(c) Another digest of the genomic DNA is carried out by a different enzyme

(d) DNA fragments of different size are recovered after carrying out gel electrophoresis

This question was addressed to me in an online interview.

My enquiry is from Cloning the cDNA and Specialized Libraries in chapter Libraries Construction of Genetic Engineering

Answer 1

Correct choice is (b) The size of the restriction fragment can be known by carrying out southern blotting

Best explanation: For the construction of a subsection of the library, some steps are followed. The size of a particular restriction fragment on which gene is located is known at times. The size of the fragment can be known by carrying out southern blotting. After the size is known, another digest of the genomic DNA is carried out and is done by the same enzyme. DNA fragments of the approximately same size are recovered from the gel after carrying out gel electrophoresis. They can be further cloned into a vector.