So one of our readers asked us this question the other day: Why have we not used IVF to impregnate an elephant with a wooly mammoth yet? What barriers are stopping us? Is it the science or the ethics of bringing back such an old animal?
ANSWER
There are both scientific hurdles and ethical concerns that need to be addressed.
Ethical
Someone else can probably expand on this more, but the most interesting conversation I’ve seen in the ethical debate is ‘where are they going to go?’ Basically, what reason are we doing this for? Are we just bringing back a wooly mammoth-like animal so that we can say that we did it? Are we doing it as a prototype to see how far back we can recover an extinct animal from? Or are we trying to re-establish wooly mammoths into a habitat in the wild?
I think that the first two options are of limited scientific utility, and the last option is of some ethical utility if you highly value up-front biodiversity. However, introduction of the wooly mammoth into pretty much any habitat would shock the ecosystem (they are, at this point, invasive species).
One ethical argument in favor of cloning mammoths is to do so in order to reintroduce them to a reconstructed “Mammoth Steppe” ecosystem.
Arctic permafrost contains a massive amount of sequestered carbon. As global temperatures warm, permafrost could thaw releasing methane and CO2, which may further increase global warming in a feedback loop. If the mammoth steppe ecosystem could be restored, these grasslands may insulate permafrost and prevent it from thawing. Herbivores capable of withstanding arctic temperatures are a necessary part of this ecosystem. Mammoths are not the only suitable herbivores, but cloning them would probably help, even if only by providing the necessary public interest to get a project such as this off the ground.
Scientific
There are something in the neighborhood of 1.5 million nucleotide differences between wooly mammoths and Asian elephants (not all of these will be phenotypically significant). In Jurassic Park, they sort of glossed over the ‘putting together the dinosaur genome’ part. Realistically, you can’t just print out chunks of custom designed DNA and paste them together into a full animal genome, the genomes are just too big. George Church’s group has instead been using CRISPR to introduce changes to genes that they think will result in noticeable phenotypic changes. Once you’ve introduced enough of those changes, then you’re probably ready to try to start IVF work.
Somatic cell nuclear transfer has not been successfully performed on elephants (we haven’t cloned elephants yet), so it would take some years to work out the kinks in that (generally, each species requires extra legwork to get cloning to be viable). So we are still years away from being able to actually get something that resembles a wooly mammoth born.
