Question

Choose the correct statement for cosmids.

(a) It can be regarded as lambda substitution vector

(b) Less amount of phage DNA is deleted

(c) Only cos packaging sites are left

(d) It doesn’t contains a origin of replication

I have been asked this question by my college director while I was bunking the class.

The origin of the question is Lambda ZAP and Cosmids in section Other Vector Systems for E of Genetic Engineering

Answer 1

Right answer is (c) Only cos packaging sites are left

Explanation: Cosmids can be regarded as lambda replacement vectors. More amount of phage DNA is deleted and only cos packaging sites are left. There are no coat protein genes left. It also contains an origin of replication.