Final answer:
An absence or significant decrease in shmoo formation would be observed in the Δformin strain, supporting the hypothesis that formin is essential in the signal transduction pathway for shmoo formation in yeast.
Step-by-step explanation:
If the hypothesis that formin is required for the signal transduction pathway leading to shmoo formation is correct, then in a Δformin strain (a strain with a deletion of the formin gene), one should observe an inhibition or complete absence of shmoo formation. Shmoos are structures that yeast cells form as a part of the mating process in response to mating pheromones, indicating successful signal transduction. Without formin, which presumably plays a key role in this pathway, the yeast cells would be unable to properly respond to the mating signal, thus failing to form a shmoo. This would provide evidence supporting the hypothesis that formin is essential for this specific signaling pathway.
If the hypothesis is correct that formin is required for the signal transduction pathway leading to shmoo formation, the result observed in the Δformin strain would be a loss or reduction in the ability to form shmoos. The Δformin strain would show a decreased response to the signal that triggers shmoo formation compared to wild-type strains.