Development of Cloning by Nuclear Transfer

In 1952 the American biologists Robert Briggs and Thomas King demonstrated that the nucleus of an early embryonic cell from a northern leopard frog, transplanted into an egg cell whose own nucleus had been removed, could direct the development of that egg into a normal embryo, producing thirty five complete embryos and twenty seven tadpoles from a hundred and four attempted transfers. Their technique, called somatic cell nuclear transfer, was the first demonstration that the genetic material of an early embryonic cell retained the instructions needed to build a whole organism, long before related nuclear transfer techniques produced the first cloned mammal decades later.