  We estimate the quark-mass dependence of the topological susceptibility with
dynamical overlap and clover fermions. Unquenching effects on the
susceptibility turn out to be well approximated by a reweighting of a quenched
ensemble with a low-eigenmode truncation of the fermionic determinant. We find
that it is most likely due to the explicit chiral symmetry breaking of the
fermion action that present day dynamical simulations do not show the expected
suppression of the topological susceptibility.
