Go Toward the Light: Using the DGRP to Search for Genes Associated with Light Addiction

Friday, February 12, 2016
Emma Christensen, NCSAS, Durham, NC
These are the first steps in a study of light addiction. In our technological world today, we are surrounded by screens. Although these phones and computers have streamlined communication and aided humanity in many other ways, they also have adverse effects. The light that emanates from these electronic devices has been shown to harm our circadian rhythms. The dangers of staring at screens are widely known, yet we still insist on looking at our electronic devices more often than is good for us. One could argue that it is only the content of the devices drawing the user in, but could the light also be a factor in this obsession? Could humans be suffering from light addiction? Genes have been found to be related to other addictive behaviors.  Could there be a genetic relationship to light addiction?  This study tested the hypothesis that there are genes involved with light addiction. To test the hypothesis, Drosophila, was used as a model organism to identify genes that could possibly cause light addiction. A powerful new tool called the Drosophila Genetic Reference Panel (DGRP) streamlines genetic screens, making Drosophila an ideal model organism for early genetic research. Thirty recombinant-inbred lines were tested three times each using a simple T-Maze made of Tygon tubing. One arm of the T-Maze allowed light to enter, and the other was wrapped in electrical tape to restrict all light, then baited with a mixture of yeast and water, made inaccessible to the drosophila by to a small piece of cotton. The drosophila were introduced into the T-Maze and left for three hours to choose between food and light. At the end of the period, those that were at the light were deemed to show signs of a strong and harmful attraction to light, choosing light over food. The results received from the DGRP revealed over 10 thousand Small Nucleotide Polymorphisms (SNPs) that were significantly correlated with this harmful attraction. The 62 most significant (lowest p-values) of these SNPs were analyzed, and 26 genes were discovered.  These genes were shown to be involved in activities such as sensory organ development, neurogenesis, motor activity, and optic lobe development.  These results give a starting point for further research.