Comparison between the simulation including all the giant planets and simulation deep21 (from 39 au), where only Neptune and Uranus are present. The snapshots were taken at 5 Myr, when the disc phase (and therefore the inward migration) has already ended and the planets are undergoing outward migration, as highlighted by the different locations of the MMRs. The simulations diverge during the outward migration because of the enormous scattering efficiency of Jupiter.