An organism’s circadian rhythm is an endogenous process that regulates 24-hour cycles within the organism, such as the sleep and wake cycle. A related phenomenon is photoperiodism, which is the response of an organism to change in day length. Different photoperiods commonly affect the development of an organism. In this project, photoperiodism was studied using Neurospora crassa. The goal of this project is to determine how Neurospora measures day length, and if it follows the internal coincidence hypothesis or the external coincidence hypothesis. To do this, we used a protoperithecia assay, which is described as the following. First, 91 different strains of Neurospora were grown in test tubes. Conidia from the tubes was inoculated onto plates and the plates were put into different photoperiods. After 12-14 days, the plates were taken out and the number of protoperithecia (female reproductive structures) on each plate was counted as our phenotype. This data was then analyzed using QTL analysis. One major QTL was found on chromosome 5, along with its significant genetic marker Nc-M3836. Using this information, we used Fungi Database to find the target region around this genetic marker on chromosome 5. We then performed the protoperithecia assay on Neurospora clock, photoreceptor, and target region mutants. This was done to determine if removing one gene has an affect on protoperithecia growth and therefore on the circadian clock.

Items