  We discuss the relation between leptogenesis and the MNS phases in the class
of see-saw models called light sequential dominance in which the right-handed
neutrinos dominate sequentially, with the dominant right-handed neutrino being
the lightest one. The heaviest right-handed neutrino then decouples, leaving
effectively two right-handed neutrinos. Light sequential dominance is motivated
by SO(10) models which predict three right-handed neutrinos. With an
approximate Yukawa texture zero in the 11 position there are only two see-saw
phases which are simply related to the MNS phase measurable at a neutrino
factory and the leptogenesis phase. The leptogenesis phase is predicted to be
equal to the neutrinoless double beta decay phase.
