$Q^2$-evolution of spin-dependent parton densities

We discuss the NLO evolution of quark transversity densities and of the parton distribution function for linearly polarized gluons in a linearly polarized hadron. A supersymmetric relation between the NLO evolution kernels for transversity and for linear polarization is found. We also study the implications of NLO evolution for Soffer's inequality and the prospects of measuring transversity densities in polarized Drell-Yan at RHIC.