Final answer:
In the process of interrupted conjugation in E. coli, using the fact that leu appeared at 6 minutes, azi at 9 minutes, and pro at 12 minutes, the azi gene is determined to be the middle gene.
Step-by-step explanation:
To determine which gene is in the middle during the process of interrupted conjugation in E. coli, we look at the timing of when the donor genes appeared in the recipient.
The genes were transferred at different times: azi at 9 minutes, leu at 6 minutes, and pro at 12 minutes.
The shortest time for transfer was 6 minutes for leu and the longest was 12 minutes for pro, indicating that leu entered the recipient cell first and pro last. Therefore, the azi gene would be in the middle, as it was transferred after leu but before pro.