Surrogate mother? Richard Towell
Finally, if embryos that developed normally for a few days could be produced, they would have to be transferred to surrogate mothers to develop through pregnancy. Embryo transfer is only carried out routinely in fewer than a dozen species, and the elephant is not one of them. Success in embryo transfer depends upon introducing the embryo to a womb that is in a receptive state. The mechanisms that bring about this state in elephants are currently being defined by research in a number of zoos.
Taken together, it can be seen that there is biological uncertainty about the availability of viable cells, and that several complex techniques would have to be developed for cloning of mammoths to be successful. There is no guarantee that these techniques are even biologically possible. There may be unknown differences between species that would prevent the procedures that we developed in sheep being successful in mammoths.
Mammoth stem cells
An alternative ambition would be to try to use mammoth cells to produce stem cells. In several different species it is possible simply by the introduction of four selected proteins to give adult cells the characteristics of embryo stem cells. The four factors give embryo stem cells their unique characteristics and were found to be able to impose these characteristics on skin cells. This type of stem cell can be grown for very long periods in the laboratory while retaining the ability to form all of the tissues of the body.
They would provide extraordinary opportunities to compare mammoth cells with those of elephants. This knowledge would be of fundamental biological interest. It would enable us to begin to answer groundbreaking questions. What are the differences between the cells and tissues of these species? What are the similarities? The mammoth lived in a different climate, so was the metabolism of their cells different? Does this information cast any light on the cause of extinction of mammoths?
Stem cells of this type can also be induced to form gametes. If the cells were from a female, this might provide an alternative source of eggs for use in research, and perhaps in breeding, including the cloning of mammoths.
From a male, they would be sperm, and they might be able to fertilise eggs to produce a new mammoth embryo. It would be interesting to know if mammoth sperm could fertilise eggs of the elephant. If so, would the embryos develop to term to produce a hybrid animal?
Only a small proportion of mixed matings between species produces viable offspring, but the mule is one example and has been used by humans for centuries.
Labrador-mammoth hybrid? PetsAdviser
In all of these discussions it is necessary to consider the welfare of the animals. Mammoths lived in cold climates, whereas their current relatives including potential surrogate mothers live in warmer regions.
It would be essential to provide mother and clone with the appropriate environment of temperature, moisture and diet. It would almost certainly be necessary to keep the animals in captivity, so it would be essential to provide as interesting an environment as possible. Ideally this should include other elephants, mammoths or hybrids to provide social interaction for the animal.
So while unlikely at present, the development of some form of mammoth creature or hybrid might be possible in the longer term, the research of which could lead to major biological discoveries and advances.