Evaluation of the isospin asymmetry of the nucleon structure functions with CLAS++

The possibility to estimate the isospin symmetry breaking effects in the non-perturbative part of F2 structure function of the charged lN deep-inelastic scattering data, which will be provided by the CLAS++ detector of the upgraded TJNAF machine at Q2≈2 GeV2, is discussed. The problems of the Gottfried sum rule extraction are also considered.