We numerically studied Bose–Fermi mixtures in one-dimensional optical lattices using a modified Bose–Fermi–Hubbard model. We derived the modified Bose–Fermi–Hubbard model in a tight-binding approximation, retaining the terms which were usually ignored. Quantum Monte Carlo simulations were then performed on the model to demonstrate a bosonic Mott transition of the Bose–Fermi mixtures. This gives another scenario of the fermion-induced decoherence of bosons observed in some experiments.