Several ways have been proposed on how it could be done. For example, inseminating an Asian elephant cow with a reconstructed mammoth sperm and subsequent absorptive breeding. A more effective and modern idea is the CRISPR method that is favourised by a number of scientists today. To put it simply, CRISPR is about cutting (splicing) a DNA strand (in this case, an Asian elephant's) at the loci where it differs from the template (mammoth) and to exchange the original base pairs with the ancient ones to create an ever increasingly mammoth-like functional DNA strand.
Renomed geneticist George M. Church and his lab at the Harvard University are involved in a project that tries to genetically reconstruct a mammoth on long-term sight this way. Now they managed to splice ancient mammoth genes into the genome of an Asian elephant and the ancient genes did indeed show normal function in the A. elephant cells. Allegedly these genes are involved in typical mammoth characteristics, such as subcutaneous fat, small ears and hair growth, but I don't know how reliable that claim is. The results have not been published in a peer-reviewed paper yet because there is more work to do, Church says.
Something similar has already been achieved with a gene of the Thylacine responsible for cartilage formation. Go here for the paper.
Does this bring us closer to seeing a living woolly mammoth again? Not necessarily. But at least it has been shown that it is possible to insert some mammoth genes into the genome of an extant elephant and to have them working normally. Of course it will be possible to create a full mammoth genome this way, as long it is fully resolved, but there are still practical issues, such as using a female elephant as a surrogate and perhaps also epigenetics. We have to be patient.
For more article on cloning extinct animals, go here:
- Clong as a chance for the Wisent?
- Extinct species/subspecies that could be revived through cloning
- Complete genome of an aurochs sequenced