How are transformants selected from nontransformants?
| 1. | Presence of more than one recognition site in the vector DNA. |
| 2. | Presence of alien DNA into the vector DNA results into insertional inactivation of selectable marker. |
| 3. | Antibiotic resistance gene gets inactivated due to insertion of alien DNA. |
| 4. | Both 2 and 3. |