Scientists in Japan created the first transparent frog by selectively breeding frogs with clear skin over multiple generations. Only about one in sixteen frogs produced from this breeding was fully transparent from tadpole to adult stages. The internal organs of these transparent frogs are visible through their skin without dissection, allowing researchers to observe organ growth and track how medicines and toxins affect metabolism. Transparent frogs could also be used to study disease progression and treatment by injecting illuminating proteins to light up genes involved in processes like cancer development. Researchers hope transparent frogs can replace dissection in classrooms and provide an inexpensive model for various areas of biological study.