  Quantum shell effects are known to affect the formation of fragments in
nuclear fission. Shell effects also affect quasi-fission reactions occurring in
heavy-ion collisions. Systematic time-dependent Hartree-Fock simulations of
50Ca+176Yb collisions show that the mass equilibration between the fragments in
quasi-fission is stopped when they reach similar properties to those in the
asymmetric fission mode of the 226Th compound nucleus. Similar shell effects
are then expected to determine the final repartition of nucleons between the
nascent fragments in both mechanisms. Future experimental studies that could
test these observations are discussed.
