CFTR and cystic fibrosis: Both the pig (Rogers et al. 2008a, 2008b) and the sheep (Fan et al. 2018; Viotti Perisse et al. 2021) models of CF meet these criteria, though interestingly the gross impact of loss of CFTR function on the developing lung is not identical in the two species (Meyerholz et al. 2018; Van Wettere et al. 2022).