RHO and retinitis: An experiment to humanise rhodopsin included fusion of green fluorescent protein (GFP) at the C-terminal end, in order to visualise Rhodopsin-expressing cells in the retina with high sensitivity; however, the GFP fusion generated a recessive allele, unexpectedly causing ﻿death of rod photoreceptor cells, thereby providing a useful, even though unintended, model for retinal neurodegeneration106.