Notably for the study of AD-DS, this model does not contain an additional functional copy of APP. Most recently, the Tc(HSA21,CAG-EGFP)1Yakaz/J (TcMAC21) model (Kazuki et al., 2020) was created which carries a mouse artificial chromosome (MAC) with a nearly complete copy of Hsa21; this model is not mosaic because of the use of mouse centromere to carry the human gene-content. The gene discussed is APP; the disease is Alzheimer disease.