The GATE Grind

GATE 2023 BT – Question 45

Recombinant DNA Technology and Other Tools in Biotechnology · Recombinant DNA technology: Restriction and modification enzymes, vectors, expression vectors, libraries, gene isolation and cloning, transposons, gene targeting · 2 marks · Multiple select

Which of the following vector(s) is(are) used to clone a DNA fragment of size 220 kb?

  1. Bacterial artificial chromosome
  2. Yeast artificial chromosome
  3. Cosmids
  4. pUC19 plasmid

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Correct answer: (A) Bacterial artificial chromosome; (B) Yeast artificial chromosome

Explanation

Compare the insert size (220 kb) with the capacity of each vector.

VectorTypical insert size
pUC19 plasmidup to about 10 kb
Cosmidabout 35 to 45 kb
Bacterial artificial chromosome (BAC)about 100 to 300 kb
Yeast artificial chromosome (YAC)about 200 kb to 2 Mb

A 220 kb fragment fits in a **BAC** and in a **YAC**, but is far too large for a cosmid or a plasmid.

Answer **A and B**.