Biology · Principles and Processes in Biotechnology

Which of the following characteristics is most essential for a cloning vector to facilitate high copy number of the linked DNA in host cells?

1. A
   Presence of unique restriction sites for multiple antibiotic resistance genes
2. B
   An origin of replication (ori) that supports high copy number
3. C
   Presence of \( \beta \)-galactosidase coding sequence for insertional inactivation
4. D
   A selectable marker that encodes resistance to chloramphenicol only