Unlike current research into gene therapy, which aims to cure disease, Crakes' vaccine was designed to protect just two people from a pandemic which he triggered. Genetic engineering of humans is also used inappropriately in Oryx and Crake to create the Crakers during Crake's Paradice Project. The Crakers have had their genes altered to create humans with specific traits. For example, they had skin resistant to ultraviolet rays and the ability to purr to heal themselves. Crake, “worked for years on purring. Once he discovered that the cat family purred at the same frequency as ultrasounds used on bone fractures and skin lesions and those equipped with their own self-healing mechanism... the trick was to modify the hyoid apparatus and the voluntary nerve. connected pathways and neocortex control systems adapted without hindering speech abilities” (Atwood