Theoretically, it would be possible to recreate a mammoth by genetically modifying an elephant embryo to carry all of the 400,000 important genetic differences that exist between the species. With today's technology, however, scientists can only make one genetic change at a time.
Next year, scientists are expected to reveal the full genetic code of our own most recent ancestor, the Neanderthal. Genetic differences between Neanderthals and modern humans could reveal why humans came to be the dominant species on Earth.
It poses an interesting moral question. If one could recreate a mammoth, one could therefore recreate a Neanderthal.
1. Presumably you put the new mammoth in a zoo 2. Presumably you put the new Neanderthal........