  In the quantum statistical parton distributions approach proposed more than
one decade ago to describe the parton structure, new properties are now
understood, in particular, the relation between quarks and antiquarks which
leads to very specific properties. The simultaneous treatment of unpolarized
and polarized Parton Distribution Functions (PDFs) allows a determination of
thermodynamical potentials (the master parameters of the model) which drive
their behavior and as a consequence those of the structure functions. The
existence of a possible relation between the gluon and a $q~\bar q$ pair leads
to define a toy model for the unpolarized and polarized gluon. In view of
forthcoming experimental results in the large $x$ region specific predictions
made by the model are presented.
