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 F 2 structure function of the charged lN deep-inelastic scattering data, which will be provided by the CLAS++ detector of the upgraded TJNAF machine at Q 2 ≈ 2  GeV 2 , is discussed. The problems of the Gottfried sum rule extraction are also considered.