The first cloned animals were created by Hans Dreisch in the late 1800's. His main goal was to prove that genetic material is not lost during cell division.
In 1902, embryologist Hans Spemman, separated a 2-celled embryo of a salamander. He later separated a single cell from a 16-celled embryo. In these experiments, both the large and the small embryos developed into identical adult salamanders. He then stated that no genetic material was lost as cells grew and divided.
After a long wait for new cloning discoveries on November of 1951, a team of scientists in Philadelphia cloned a frog embryo. They took the nucleus out of a frog embryo cell and used it to replace the nucleus of an unfertilized frog egg cell. Once the egg cell noticed that it had a full set of chromosomes, it began to grow. This process is called nuclear transplant and it was made that day. We still continue to use this method but made few changes to it.
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