There is another approach, however. Scientists could use the scraps of DNA they do find in preserved bodies to build up a map of a mammoth’s genome. “Then you would use the same techniques that are employed in creating transgenic mice to make stretches of DNA – using your map as a guide – that you would then put into the embryo of an Asian elephant embryo which is the closing living relative of a mammoth,” said Hofreiter.
“Bit by bit, you would continue with this process with separate pieces of mammoth DNA until you had completely replaced the DNA in your elephant embryo with mammoth DNA. You would now have an embryo with a mammoth genome it. This would then be placed in a female elephant in whom the embryo would develop to birth.”
There are many difficulties with this approach, however. “A key point to remember is that elephants and mammoths each have about 4 billion DNA bases in their genomes,” said Hofreiter. “However, the maximum size of the DNA section you can add is about 1 million bases. So you would have to repeat the process sequentially 4,000 times – without mishap – to create your mammoth embryo. The chances of that happening are also essentially zero.” On top of these problems there is the simple issue of differences in proteins that exist between the Asian elephant that would be used as a surrogate mother and the mammoth embryo you have created. “It is quite possible that these differences would be big enough to make the embryo incompatible with the elephant. It is a further factor to suggest that mammoth cloning is not going to happen for a very long time indeed.”