Question

Which vector is not suitable for Genomic DNA library construction?

• A. \(\lambda\) replacement vector
• B. Yeast Artificial Chromosomes
• C. Bacterial Artificial Chromosomes
• D. Plasmids

Hint:

• Choice of vector for genomic library depends on insert size capacity:
  • Plasmids Small inserts (up to ~15 kb).
  • Lambda (\(\lambda\)) phage vectors Moderate inserts (~9-23 kb for replacement vectors).
  • Cosmids Larger inserts (~30-45 kb).
  • Bacterial Artificial Chromosomes (BACs) Large inserts (~100-300 kb). Stable.

Answer 1

The Correct Option is D

In genomic DNA library construction, the choice of vector is crucial for ensuring the stable maintenance and easy replication of large DNA fragments. Let's discuss the suitability of the given vectors:

• \(\lambda\) Replacement Vector: Used for genomic libraries as it can carry fragments up to 15-20 kb in size.
• Yeast Artificial Chromosomes (YACs): Suitable for large fragments, as they can accommodate up to 1 Mb.
• Bacterial Artificial Chromosomes (BACs): They carry large DNA fragments, typically 100-300 kb, making them ideal for genomic libraries.
• Plasmids: Generally hold smaller DNA inserts, typically less than 10 kb, and are thus not suitable for genomic DNA library construction which often requires larger fragments.

Therefore, among the given options, Plasmids are not suitable for genomic DNA library construction due to their limited capacity to hold larger DNA inserts.