n the 1930s, scientists discovered differences in the ability of humans to taste a bitter synthetic compound called phenylthiocarbamide, or PTC, and they determined that the trait was controlled by genetics (the actual gene for PTC sensitivity was discovered in 2003). For PTC “tasters,” even tiny concentrations of the compound are extremely bitter, 70-563 while “nontasters” experience little or no taste to the same concentration of PTC. “In some ways, bitter-taste sensitivity seems to be a trivial trait, but early geneticists recognized that this trait was special, 70-565 for a variety of reasons,” said Dr. Wooding, an assistant professor with UT Southwestern’s Eugene McDermott Center for Human Growth and Development. 70-567 “Bitter-taste sensitivity is crucially important in protecting the human body from toxins in the environment. By enabling us to perceive noxious chemicals in potential foods—especially toxins used by plants to 70-568 defend themselves against herbivores—bitter taste probably helped our early ancestors avoid poisoning,” he said.