Day 29 finishes off Chromosome 1. It has 86 protein-coding genes, half of which are olfactory receptor genes. There are lots of clusters of OR genes and we will talk about them when we hit them again. Something more unique today is the gene for OPN3 (opsin 3), also known as panopsin, a light-detecting opsin protein expressed in your brain, skin, and other organs.
It’s not yet clear why we make an opsin outside of our eyes. In the skin, they may help cells detect UV exposure. Geckos use the opsin in their skin to change color. More strangely, panopsin in the brain may be used to directly detect light through the skull to entrain the circadian rhythm and melatonin cycle.
Click here to see your panopsin gene last day of Chromosome 1.