Humans vs. Fruit Flies

                                                   Humans vs. Fruit flies

How similar are humans to fruit flies? Our first instinct would be that they are extremely different, but according to the research of Dr. Cavanaugh and that of Dr. Fumika N. Hamada it is proven otherwise. In reality, results of research show that one of the biggest similarities between Drosophila and human brains is the comparable genetically driven internal clock.

The study done by Dr. Hamada, posted by Current Biology, concludes that fruit flies control their body temperature through circadian rhythm. For example, they “exhibit a daily temperature preference rhythm that is low in the morning, high in the evening” (Hamada.) Despite the fact that they are cold blooded, fruit flies show body temperature rhythms that are very similar to those of humans. The study subjected many “genetically altered flies to different degrees of light and darkness” and then studies their brains (Hamada.) Afterwards, the scientists were able identify a pacemaker neuron in the fruit fly brain called DN2 that controls the fly’s temperature rhythms in a similar manner to that of the hypothalamus in the human’s brain. Therefore, this study was able to show that Drosophila have a similar circadian clock system to humans.

Furthermore, Dr. Cavanaugh spoke about how he was trying to map the circuit of the circadian clock in fruit flies to determine which cells are communicating with each other in the brain and in which order. Dr. Cavanaugh’s research included a different circadian rhythm that also demonstrated the close relationship between fruit flies and human brains. He determined the activity of fruit flies by placing them in light and in dark environments and recorded when they started and ended activity. Then all environmental cues were removed, yet the flies continued to show activity and rest in the same manner as if they were subjected to light and darkness. Since this circadian rhythm persisted in the absence of external environmental cues, it was concluded that they have an internal clock resulting into natural rhythms in the flies. Their internal clocks showed that they had periods dividing into almost 24 hours; their homeostasis methods are extremely similar to how the human hypothalamus functions.  Results of both studies are very similar because they show the close structure and function of the fruit fly brain to the human brain.

Fruit flies were interesting to study in both cases because they have around 70 % of human genes and many of those are the ones that include specific mutations or diseases. Those two studies showed different rhythms that are based upon the internal clock that is similar in both humans and fruit flies. Therefore, most conclusions that are made concerning the circadian rhythms and circuit mapping of fruit flies’ brains can ultimately be translated into mapping of the human brains. Eventually this could be a method used to predict and design models of human development and diseases.

Cavanaugh D., Geratowksi J., Wooltorton J., Spaethling J., Hector C., Zheng X., Johnson E., Eberwine J., Sehgal A. Identification of a circadian output circuit for rest:activity rhythms in Drosophila. 24 April 2014. 689-701

"Newsroom." Fruit Flies Reveal New Evolutionary Link for Studying Human Health. N.p., n.d. Web. 12 Oct. 2015.

Image from: http://www.kurzweilai.net/decoding-the-human-brain-with-help-from-a-fly