Cloning has naturally been going on for thousands of years already. Actually, the definition of a clone is a living thing created from another, leading to two organisms with identical DNA. Some examples of the product of DNA replication are the reproducing mode of some plants, the regeneration of earthworms and even the creation of identical twins. However, recent developments provided humans the ability to intentionally create clones by working on cells. Even more recently, Japanese and Russian researchers entered the process of cloning a mammoth.