  We study the evolution of parton distributions down to low scales by
considering several of their Mellin moments. For the initial conditions, we use
a broad array of current parton density fits. Confirming earlier findings in
the literature, we conclude that current determinations of parton distributions
are incompatible with the idea that gluon or antiquark densities are generated
by purely perturbative radiation as it is encoded in the DGLAP evolution
equations.
