How to Clone a Mammoth by Beth Shapiro

A rare foray into non-fiction for me, as I share my thoughts on Beth Shapiro’s How to Clone a Mammoth.

I bought the book after hearing Shapiro talk at this year’s Hay Festival.  I found the event to be both amusing and informative, and pitched at such a level that everyone, even those with no prior knowledge of the subject – de-extinction – could gain something from it.  The book is pitched at a similar level.  It goes into more detail about the technical aspects of cloning, but using analogies that people can easily relate to, and without unnecessary use of jargon.

How to Clone a Mammoth explores several questions:

  • Could we bring back extinct species, such as the mammoth and the dodo?
  • What are the methods for doing so?
  • If we could, should we?
  • Which species are viable options for de-extinction?
  • Are some species ‘more worthy’ than others?
  • What are the benefits of bringing back species that are currently extinct?
  • Are there any downsides?

There are a number of methods that are under consideration for de-extinction.  Without getting too technical, they are:

  1. Back breeding – taking animals that are alive today, but similar to an extinct species, and mating them to encourage certain traits to be carried into the next generation (this takes a while).  This method has the benefit that we’ve been doing it for years, to develop faster race horses, for example
  2. Genetic engineering – would require DNA samples of extinct species, which can then be used to amend the relevant genome sequence of a closely related living species – think of it as a ‘cut and paste’ in the DNA sequence
  3. Cloning – requires a viable cell from an extinct species – this has not yet been successful

Needless to say, none of these methods is straightforward.

As I mentioned, Shapiro believes that a possible step in de-extinction would be to take a species that is alive today, and ‘tweak it’ into something else.  This seems to be a potential first step in the de-extinction of the mammoth, whose closest living relative is the Asian elephant.  By finding the genomes that make a mammoth hairy, for example, could we create an elephant that could live comfortably in Siberia?  But, “If it looks like a mammoth and acts like a mammoth, is it a mammoth?” (1)  Well, kind of.  And this might actually be as close as we can get.  There’s no guarantee that cloning an extinct species will ever be possible.

Breeding in captivity would be necessary as an initial step to creating a genetically diverse, self-sustaining population that could be released into the wild.  And that would have to be the ultimate aim.  It would be a shame to bring something like the mammoth back into the world, just to have it sit in a zoo.  But where would they go?  There is a gentleman who has converted an area of Siberia into a habitat suitable for the mammoth, a place called Pleistocene Park.  This can’t be done for every species, however.  If there’s nowhere for it to go, I would suggest that this means that it’s not a viable option for de-extinction.

Breeding in captivity introduces additional problems.  Some creatures do well in captivity.  They tend to be creatures that have adapted to urban environments, and that ‘work well’ with humans.  Some creatures do not.  They don’t live as long, they struggle to reproduce.  Unfortunately for the mammoth enthusiasts, elephants fall into the latter category.

Extinction is, I think, a evocative term.  Particularly today, when so many species are endangered.  And yet, “more than 99 percent of species that have ever lived are now extinct” (2).  Extinction is a natural consequence of evolution.  Species fight for resources, and those that lose become extinct.  The strong survive.  The issue comes where we (humans) have caused a species to become extinct, through over-hunting (aside from the days when this was purely for our own survival) or through the destruction of natural habitats.  This changes things.  This is not natural selection.  This is evidence of our negative impact on the planet and those we share it with.  I think that the word extinction evokes guilt in us.

Does this mean that species that have become extinct because of our impact are the more viable candidates for de-extinction though?  it would assuage our guilt, certainly.  However, de-extinctifying* an species sets a dangerous precedent.  If we have the ability to de-extinctify a species, does this mean that we can bring a species back at the drop of a hat?  Would this mean that people care less about animal conservation?  In my opinion, the answer to both of these is, emphatically, no.  There’s a proverb that states that ‘prevention is better than cure’ which I think applies here. This will always be too complex, too expensive a process to mean that conservation efforts are sidelined or become irrelevant.

So, assuming that we could de-extinctify a species, should we?

There are potential benefits:

  • Existing ecosystems can be improved.  Mammoths, and other large herbivores, “can transform a mostly barren tundra into a rich grassland” (3).  And in a relatively short space of time, too.  Their movements encourage the dispersal of seeds, the recycling of nutrients essential to plant life, etc.  In the 1990s, the Cascade Mountains wolf was reintroduced to Yellowstone National Park.  Despite initial concerns, this has actually helped to stabilise the ecosystem which had become unbalanced since the decline of this predator, and has encouraged the development of certain plant and animal species that were struggling, with no adverse impacts on other species
  • The science can be adapted to preserve existing species.  If a species is about to become extinct because of a vulnerability to a disease, for example, it may be possible to preserve it.  There is the example of the American chestnut tree, which was nearly wiped out by a foreign fungus – Through genetic engineering, these trees are now making a comeback
  • We can also learn a significant amount about both genetic engineering and evolution, science that may help humans and other animals in areas such as medicine

But, there are counter arguments:

  • Some species may carry harmful pathogens that we would also, unintentionally, bring back
  • If an ecosystem has developed without a particular species, reintroducing it may cause imbalance that may ultimately be detrimental.  How much does a creature such as a mammoth eat?  In the case of carnivores, will the result be the extinction of a species upon which they prey?
  • And in considering the how, these creatures will initially need a surrogate mum – somewhere to stay for the gestation period, if you like.  This could be harmful to animals, if, for example, the newborn is larger than the host species is used to giving birth to.  Shapiro is adamant that no harm should could to any creature through this, a sentiment I echo wholeheartedly

I’ve tried to show here that while I think that this is an interesting and exciting area of science, I don’t expect to see a mammoth any time soon.  There are many questions to consider, and much work to do, but I hope we get there.  I think that the world will be a better place for it.

One final point.  in my last post on Jurassic Park, I mentioned that cloning a species from DNA trapped in amber is not possible.  This is because amber does not preserve DNA.  It is a permeable substance, and so any DNA contained within is not sufficiently protected from substances that are harmful to it.  Additionally, amber may be subjected to extreme heat and / or pressure, both of which have detrimental impacts on the survival of DNA.

References:

(1-3) Beth Shapiro, 2015, How to Clone a Mammoth, Princeton University Press.

*Shapiro touches on the grammatical difficulties around the topic of de-extinction.  The language is awkward, but I’ve done my best to keep it simple and sensible.

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