Non-uniform-perfectness conjecture for mapping class groups

Let ${\cal M}_g$ be the mapping class group. Recall that a group ${\varGamma}$ is uniformly perfect if there is a natural number $N$ such that every element of ${\varGamma}$ is a product of at most $N$ commutators. Non-uniform-perfectness conjecture. The mapping class group ${\cal M}_g$ is not uniformly perfect for every $g\geq 3$. The source notes that ${\cal M}_g$ is perfect for $g\geq 3$ and states that this conjecture was subsequently proved by Matsumoto and Morita, so its status is solved.