Question

Cosmids are ______

• A. Naturally occurring vector
• B. Vector constructed using plasmid DNA and cos site of Lambda phage DNA
• C. Plasmid DNA with RNA
• D. None of the above

Answer 1

The correct option is B

Vector constructed using plasmid DNA and cos site of Lambda phage DNA

Cosmids can be used to clone DNA fragments up to 45 kb in length. A cosmid is a type of hybrid plasmid that contains a Lambda phage cos sequence. The DNA sequences of Cosmids (cos sites + plasmid = cosmids) are originally from the lambda phage. They are often used as a cloning vector in genetic engineering