Top panel: evolution of a 1.8   M_⊙ star in the HRD (PMS phase in full black and MS phase in dashed grey) crossing the γ Dor IS (thick black lines – HS02). Middle panel: variation in its CC mass from the PMS phase to the early MS phase (X_c = 0.69). Bottom panel: Evolution of the ℓ = 1 modes period spacing as a function of the effective temperature of the star from the PMS to the end of MS (point E).