Final answer:
The yeast two-hybrid system requires a single yeast cell to harbor two different plasmids, the binding domain and activating domain of Gal4 to retain their functions, and β-galactosidase synthesis under the control of UASG. However, the condition that is not necessary is UASG being situated between the Gal1 and Gal10 gene sequences.
Step-by-step explanation:
The necessary conditions of the yeast two-hybrid system include:
- A single yeast cell can harbor two different plasmids simultaneously.
- Both the binding domain and the activating domain of Gal4 retain their individual functions after being separated by recombinant DNA methods.
- β-galactosidase synthesis is under the control of UASG.
Therefore, the condition that is not necessary is (c) UASG must be situated between the Gal1 and Gal10 gene sequences.