The Circadian Rhythm: An Experiment Using Transgenic Fly

Name: Tan Tee Hng Class: MB1102 Module: Molecular Genetics Date: 6th January 2013 Circadian Rhythms From this experiment, using transgenic fly that can glow in the dark, a study of circadian rhythms was performed. Circadian Rhythm is like an internal body clock(biological clock) of an animal. And results obtained from experiment conducted with transgenic glowing fly, allowed one to come up with a few hypotheses, firstly, circadian rhythm repeats every 24 hours. When the glowing flies were placed in a dark environment for several days, they still glowed periodically for several days at the same night time, this proved that the above hypothesis is accurate. In addition, this showed that Circadian rhythm is endogenous, since the flies glowed at persistent timing despite the fact that there was no external factor, like exposure to daylight. Circadian rhythm is also shown to be entrainable, able to be affected by external factors. In the second experiment that was conducted, whereby flies were kept in a dark/light environment for five days, and then light/dark environment. Results obtained showed that shifting timings of external light source gradually shifts timings for when the fly shows per-luc gene expressions as well. The point above allows us to infer that organisms like humans which contain an intrinsic body clock can maintain a 24 hour period, however certain mechanisms in the body like sleep-wake pattern can be influenced by some factors like the changes in light and darkness. My Experience After going through this e-tutorial dry lab work, I have gotten a better understanding of how Circadian Rhythm works. Also, I have learnt how tedious it is for a lab technician or researcher to breed model organisms and incorporate genes in them to turn them into transgenic organisms. In the website that we were made to go through, I have learnt that in order to obtain fly progeny with desirable traits takes quite a while, like a month despite the fact that flies have short