Reacción a "Mice with fur reminiscent of extinct woolly mammoth created"

Woolly Mouse in Context

“Colossal have announced that they have successfully bred ‘woolly mice’, and this is a “water shed moment” in their mission to genetically engineer an arctic adapted elephant, aka “bringing back the mammoth.”

“Colossal’s team made a number of genetic changes known as “knock outs” in lab mice that are already known to produce longer, thicker, wavier -- or woollier -- coats in mice. They also made a change known to cause blonde hair colouring in mice.

“The result, therefore, of various “woolly mice” from these genetic changes is unsurprising: woolly mice have been produced in labs and by mice breeders many times before. 

Mammoth-like genes?

“Three of the genetic changes made in some of the mice were inspired by woolly mammoth DNA, but they still only show effects in mice. The mice were not edited to have a precise copy of the mammoth genes, but it is possible that these edits may have had a similar effect in both mice and mammoths (either by stopping the gene from working, or by changing the way the gene worked), but we cannot be sure about this.

“It is also not possible to tell what impact these ‘mammoth-inspired’ changes had, if any, in the Colossal woolly mouse owing to other gene edits made at the same time. 

Are we a step closer to ‘bringing back the mammoth’? 

“A mammoth is much more than just an elephant in a fur coat. While we know a lot about mouse genetics, we know much less about mammoths and elephants. It isn’t yet known which sections of the genome are vital for achieving the characters need to make an elephant fit for life in the Arctic circle. Genes that are linked to fur and fat in well-studied animals like mice are obvious targets, but the devil is in the detail. And what about other characters that are equally important? Which bits of the genome underpin the teeth and jaw changes that might be needed to accommodate an Arctic diet, for example (mammoth teeth were clearly under strong evolutionary pressure to adapt to their diet)? What about things we haven’t even discovered yet, things we don’t know we don’t know?

“Unless you decide to make EVERY edit necessary to in the genome, you are only ever going to create a crude approximation of any extinct creature, based on an incomplete idea of what it should look like. You are never going to ‘bring back’ a mammoth.

“Colossal’s Woolly Mouse experiments also show that de-extinction attempts are fraught with failure: most gene-edited embryos failed to result in live pups (less than 10%), and very few of those born were successfully edited for all target genes. This is for experiments that made a small number of relatively simple (loss of function) changes in well understood genes, using a ‘model’ lab animal as a surrogate.

“Engineering a mammoth-like elephant presents a far greater challenge: the actual number of genes likely to be involved is far higher, the genes are less well understood (and still need to be identified), and the surrogate will be an animal that is not normally experimented upon. Even if success rates are similar to those observed in the woolly mice (and they may well be lower given the greater number of edits and unknowns), there will likely need to be multiple pregnancies before a “successful” calf is born. This equates to either a very large number of surrogate dams, or – given elephant pregnancies last approximately 2-years – a very long time.

“Mammoth de-extinction doesn’t seem to be on the horizon anytime soon. 

Ethical Considerations

“Colossal’s Woolly Mouse experiments show that the physical effect of genome-editing cannot be observed until the animal experimentation stage. This will also be true in elephants.

“Although it is branded as “woolly mammoth de-extinction”, what is being proposed is an experiment to test the effect of certain gene edits on the appearance of elephants.

“For the mice in these experiments the risk was small: the effect of these gene edits already known, and were not likely to cause risk or suffering to surrogate or pup.

“We do not know the risk involved for elephants, but it could be very high.

“We do know that surrogacy is a burden on the dam, and that captive elephant pregnancies carry risks even under normal circumstances.

“Placing such a burden of risk on an elephant surrogate in pursuit of an experiment that – at best – will produce a simulacrum of a woolly mammoth, is unjustifiable.