One is the inability to replace the function of cells in the retina with a digital camera. (scientificamerican.com)
Today's humans, apes, and (some) monkeys, for instance, all have three types of cone cells in the retina. (nautil.us)
The control mice, with all genes intact, should have lost sight as photo - receptors — the light - sensitive cells in the retina — died. (sciencenews.org)