Question

a patient falls asleep every night between 6 p.m. and 9 p.m. and wakes up between 2 a.m. and 5 a.m. which gene is likely mutated in this patient? - per2 - clk - rye - bmal

Explanation:

The Period (Per) genes, especially Per2, play a crucial role in regulating the circadian rhythm. A mutation in Per2 can lead to an advanced sleep - wake cycle, which is consistent with the patient falling asleep early (6 - 9 p.m.) and waking up early (2 - 5 a.m.). The Clock (Clk) gene is involved in the molecular clock mechanism but its mutation typically doesn't present with this specific phenotype. Rye is not a known gene in the context of circadian rhythm regulation related to this phenotype. Bmal (Brain and Muscle ARNT - like protein) is also part of the circadian clock machinery, but its mutation is more associated with other disruptions in the circadian rhythm rather than the advanced sleep - wake cycle seen here.

Answer:

Per2