Q. Which of the following is the first step in cloning a gene?

[A] Isolation of DNA from an organism carrying the gene of interest.

[B] Cell culture on agar Insertion of a plasmid into a bacterium.

[C] Treatment of plasmids with restriction enzymes.

[D] All of these

Answer: A
Notes:

Cloning

Molecular cloning refers to the isolation of a DNA sequence from any species (often a gene), and its insertion into a vector for propagation, without alteration of the original DNA sequence. Once isolated, molecular clones can be used to generate many copies of the DNA for analysis of the gene sequence, and/or to express the resulting protein for the study or utilization of the protein’s function. The clones can also be manipulated and mutated in vitro to alter the expression and function of the protein.

The basic cloning workflow includes four steps:

  1. Isolation of target DNA fragments (often referred to as inserts)
  2. Ligation of inserts into an appropriate cloning vector, creating recombinant molecules (e.g., plasmids)
  3. Transformation of recombinant plasmids into bacteria or other suitable host for propagation
  4. Screening/selection of hosts containing the intended recombinant plasmid

 

 

Source: ForumIAS

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