We investigate the possibility to draw conclusions on the sign of the
spin-dependent gluon distribution, ΞG(x,Q2), from existing polarized
DIS data. The spin-dependent parton distributions Ξuvβ,Ξdvβ,ΞuΛ,ΞdΛ,Ξs, and ΞG are constructed
in the framework of a phenomenological procedure taking into account some
assumptions on signs of valence and sea parton distributions motivated by 't
Hooft's mechanism of quark-quark interaction induced by instantons. The axial
gluon anomaly and data on integral quark contributions to the proton spin,
Ξu~,Ξd~, and Ξs~, are also taken into
account. Predictions for the x- and Q2-dependencies of the polarized
proton and neutron structure functions, g1pβ and g1nβ, are compared to
experimental data. It is shown that the neutron structure function, g1nβ, is
especially sensitive to the sign of ΞG(x,Q2). The results of our
analysis supports the conclusion that this sign should be positive.Comment: 14 pages, latex, 12 figure