Answer:
The correct answer is B) Large size relative to the host chromosomes
Explanation:
A vector for clonation or expression must contain sequence elements which allow it independent replication and identification of host cells which have incorporated the vector. Among these elements are:
- Replication origin (option E): allows it to replicate independently of the host genome. Option B is the same as it.
- Restriction enzyme sites (option A): in order to cut the vector and to inser the desired gene into the vector.
- Reporter gene (option E): it allows to visualize the host cells which are expresing the inserted gene of the vector. For example, a reporter gene can codificate a fluorescent protein, thus the host cells which have expresion of the vector are fluorescent.
The only option which is unuseful is option B because if the vector has too large size, the transformation efficiency will be low. That means that fewer host cells will contain the vector after transformation.
