It is known that the mapping class group of a closed (orientable) surface is generated by elements of finite order. Is this also known to be true for $Out(F\_n)?$ A related question is the following: The mapping class group is known to be a perfect group for $g\geq 3,$ that is, it is equal to its commutator. Is this known for $Out(F\_n)?$ I can find references to the effect that the rational homology is trivial in low dimensions, but that's not quite the same...



generators of Out(F_n) and homology
$Aut(F\_2)$ is generated by torsion, and [$Aut(F\_n)$ is normally generated by $Aut(F\_2)$](http://en.wikipedia.org/wiki/Nielsen_transformation), so $Aut(F\_n)$ is generated by torsion, hence $Out(F\_n)$. 


