EXAMINATION OF THE TAS2R38 GENE AND ITS SPECIFIC NUCLEOTIDE DIFFERENTIATIONS TO DETERMINE ABILITY TO TASTE PHENYLTHIOCARBAMIDE

INTRODUCTION Although humans are essentially genetically identical as a whole, there are some minute variances in our gene coding that allow for differences in our interactions with the world. These genetic modifications may have extensive detrimental effects, small effects, or no apparent effect at all. A few of these alterations can even affect our senses. In this lab, we examine how a discovery by a scientist gives us insight into how a relative dissimilarity between humans can affect the ability or inability to taste certain chemicals. Scientist Arthur Fox learned that the chemical phenylthiocarbamide, or PTC, could be tasted by certain people while others could not (Dolan DNA Learning Center 2006). When this was revealed, it was inferred that the ability or inability to taste this substance may be genetically related. It was also possible that there was a specific gene that coded for this capability. The gene that was found to encode for the capacity to taste PTC is named the TASR38 gene (Dolan DNA Learning Center 2006). However, it is not just the gene itself that causes differences in the ability to taste this substance, but the differences of coding within certain locations of this gene. These distinctions in gene coding across human populations at nucleotide positions 145, 785, and 886 are called single nucleotide polymorphisms (SNPs), which alter the conformity of taste receptor proteins (Dolan DNA Learning Center 2006). These SNPs can also be passed down to the next generation. This can be done because SNPs have the ability to join together and create different alleles, causing differences in humans who are capable of tasting PTC (Dolan DNA Learning Center 2006). A mechanism that helps to better examine a specific region