The only normal generators of the Torelli group of a closed surface I can find is Powell's 1977 paper (where the presentation is a bit complicated and given essentially without proof). Is there any more enlightening or smaller presentation? I would also be interested in such a result for $\mbox{Aut}(\pi_1(F_g))$ (as opposed to $\mbox{Out}(\pi_1(F_g))$.

The only normal generators of the Torelli group of a closed surface I can find is Powell's 1977 paper (where the presentation is a bit complicated and given essentially without proof). Is there any more enlightening or smaller presentation? I would also be interested in such a result for $\mbox{Aut}(\pi_1(F_g))$ (as opposed to $\mbox{Out}(\pi_1(F_g))$.

EDIT Actually, it seems that in the 1980 paper of Dennis Johnson he seems to show that Torelli is normally generated by a single element, which improves the Powell result.