Dene (Athabaskan) verbs are widely known for their complex morphophonology. The most complex patterns are associated with two conjugation markers, /s/ and /n/, which are associated with a floating H tone to their immediate left. In this paper, we provide an analysis of /θe/ and /ɲe/, the reflexes of the /s/ and /n/ conjugations in Tetsǫ́t’ıné. Whereas previous accounts of these conjugations have relied heavily on morphological conditioning, we show that, once level ordering, autosegmental phonology and metrical phonology are brought to bear on the problem, morphological conditioning is not required. Within the framework of Stratal OT, we propose the Domain Reference Hypothesis, by which phonological constraints may only refer to morphological domains and their edges. In addition, we show that in Tetsǫ́t’ıné there is a correlation between phonological opacity and morphological structure, as predicted by the Stratal OT model.