Day 28 has only 35 protein-coding genes. One is CHRM3 (muscarinic acetylcholine receptor M3), encoding one of the many types of receptors on your muscles that receive signals from your nerves to move.
CHRM3 has a hodgepodge of roles on different muscles: it is responsible for receiving the signals to constrict the pupil, focus the eye, and release saliva. When your optometrist dilates your pupils, she uses drugs to turn off CHRM3.
Click here to see your CHRM3 gene on Day 28.