For example, this CRISPR/Cas9-mediated knock-in could be used to introduce human neurodegenerative disease variants into conserved endogenous killifish loci (e.g. amyloid precursor protein [APP] for Alzheimer’s disease) or to drive neurodegenerative disease variants using a pan-neuronal promoter such as ELAVL3 (though we have not examined how the expression level of ELAVL3 changes with age in this study). This evidence concerns the gene ELAVL3 and Alzheimer disease.