Furthermore, due to the fact that the two Sc alleles SC4 and SC5 are not common (< 10%) in modern cultivars (Fig. 5c), original Chinese CF cultivars of SC4 (R. chinensis) and SC5 (Mutabilis) are still useful breeding materials to introduce these rare S-alleles into CF cultivars. The gene discussed is ERMAP; the disease is cystic fibrosis.