The photoreceptor commonly involved in light entrainment of the biological clock in flies, moulds and plants is

Cryptochromes are flavoproteins that are light-sensing molecules sensitive to the blue light and are found both in plants and animals. These light-sensing molecules are involved in the circadian rhythms or maintaining the biological clock in plants and animals. Two genes Cry1 and Cry2 encode for the two cryptochrome proteins Cryptochrome Circadian Regulator 1 (CRY1) and Cryptochrome Circadian Regulator 2 (CRY2). CRY1 regulates the biological clock in insects and plants, whereas, both CRY1 and CRY2 regulates the biological clock in mammals.