Which fungus is used as a model organism in studies of circadian rhythms?

Which fungus is used as a model organism in studies of circadian rhythms? Neurospora crassa is the classic fungal model for investigating biological clocks.

This orange or red bread mold is useful because it grows readily, has a relatively simple haploid life cycle, and is genetically tractable. Researchers can connect mutations to visible traits without the genetic masking that occurs when organisms carry two chromosome sets. Its rhythmic production of spores also provides an easily measured biological output.

Neurospora has a natural reproductive cycle of roughly 22 hours, close to a daily rhythm. Light and temperature can reset or influence this clock, allowing scientists to study how environmental signals interact with clock genes and proteins.

The organism also played a major role in genetics. Experiments by George Beadle and Edward Tatum used Neurospora to establish the one-gene–one-enzyme concept, work recognized with the 1958 Nobel Prize in Physiology or Medicine. Its genome contains seven chromosomes and has been sequenced, supporting modern studies of gene regulation, development, and circadian timing.