Question

Which one of the following vector types is suitable to clone \(2000\) kb DNA insert?

• A. Bacterial plasmid
• B. Bacteriophage
• C. Cosmid
• D. Yeast artificial chromosome

Hint:

YACs are used for cloning extremely large DNA fragments, while plasmids, phages, and cosmids are suitable only for smaller inserts.

Answer 1

The Correct Option is D

Step 1: Understand cloning vectors.
Cloning vectors are DNA molecules used to carry foreign DNA fragments into host cells for replication and maintenance. Different vectors can accommodate different sizes of DNA inserts.

Step 2: Analyze bacterial plasmids.
Bacterial plasmids generally carry small DNA inserts, usually up to about \(10\) kb. Therefore, they are not suitable for cloning a very large \(2000\) kb DNA fragment.

Step 3: Analyze bacteriophage vectors.
Bacteriophage vectors such as \(\lambda\)-phage can accommodate inserts of moderate size, generally around \(20\) kb. Hence, they are also unsuitable for such a large insert.

Step 4: Analyze cosmids.
Cosmids combine features of plasmids and bacteriophages and can carry inserts of approximately \(35\) to \(45\) kb. This capacity is still far below \(2000\) kb.

Step 5: Analyze yeast artificial chromosomes (YACs).
Yeast artificial chromosomes are specially designed vectors capable of carrying extremely large DNA fragments, often ranging from several hundred kb up to more than \(2000\) kb.

Step 6: Compare all vector capacities.
Among the given options, only YACs possess the cloning capacity large enough for a \(2000\) kb DNA insert.

Step 7: Final conclusion.
Therefore, the suitable vector for cloning a \(2000\) kb DNA insert is the yeast artificial chromosome.
\[ \boxed{\text{Yeast artificial chromosome}} \]
Hence, the correct answer is option (D).