To investigate whether duplication of the region of Mmu16 from Lipi to Zbtb21 in the Dp1Tyb strain was sufficient to cause CHD, we used HREM and 3D modeling (Weninger et al., 2006), an approach we had previously used successfully to identify CHD in the Tc1 strain (Dunlevy et al., 2010). The gene discussed is ZBTB21; the disease is coronary artery disorder.