"Remarkable"

Researchers bred mice with mammoth fur for the first time

The researchers want to create a cold-resistant elephant after the "mammoth mouse".

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The mice with golden yellow shaggy fur are said to be a step towards creating the most mammoth-like elephant possible: In the USA, genetic researchers have presented "woolly mice" with mammoth-like hair. Using various genetic engineering techniques, the team from Colossal Biosciences in Dallas modified several genes in mice so that their hair structure resembles that of mammoths.

The animals illustrate the remarkable progress made in the field of genome editing, explained Colossal co-founder and Harvard researcher George Church in a company press release. Among other things, Church became famous for his announcement that he wanted to create a cold-resistant elephant that looked like a mammoth and behaved as similarly as possible.

Celebrated as a "remarkable milestone"
The creation of the woolly mice has not yet been presented in a peer-reviewed journal; the study is only available on a preprint server. Nevertheless, the publication has met with a great response among experts. Altering several genes associated with hair growth simultaneously in such a way that they are compatible with the genetic material of another species is a "remarkable milestone", explained stem cell researcher Dusko Ilic from King's College London.

Shaggy and golden yellow instead of smooth and brown - the "mammoth mouse" compared to its natural conspecifics.

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Researchers see mammoth in the distant future
The US research team initially analyzed the genomes of 121 different mammoths and elephants. From these, they selected ten genes relating to hair texture and fat metabolism that make mammoths more cold-resistant than Asian elephants and that were also compatible with the genetic material of mice.

They achieved the golden-yellow coat color, for example, by modifying the MC1R gene, which is responsible for the production of the color pigment melanin. A modification of the FGF5 gene ensures that the animals' hair is three times longer than usual.

A new creation would not be ethically justifiable
However, Tori Herridge from the University of Sheffield in England notes that less than ten percent of the genetically modified embryos were born alive, and only very few of the animals born alive had all target genes modified. The transfer of genetic mammoth traits to elephants is even more difficult - and ethically unjustifiable.

Only a few mice whose genome was altered were born alive.

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Geneticist Sergiy Velychko from Harvard Medical School also explained that the genome changes made were mouse-specific and had nothing to do with elephants or even mammoths. "We have been able to grow mice from cultured embryonic stem cells since 1981, and the first knockout mice were created in 1989 - almost 40 years ago."

False hopes
Most of the techniques used in mice could not even be applied to closely related species such as rats - "and certainly not to elephants. In elephants, even basic reproductive techniques such as superovulation and artificial insemination have never been successful". In addition, elephants - in contrast to mice - reproduce very slowly.

Mice have a gestation period of 20 days, whereas Asian elephants have a gestation period of 22 months, as the team from Dallas itself admits. Therefore, they write, mice are important models for testing the functional properties of modified woolly mammoth genes.

"Looking at these mice is a bit like looking into the past, but with a highly selective telescope," said evolutionary biologist Louise Johnson from the University of Reading in England. The technology offers an exciting opportunity to test some ideas about extinct organisms. "This is interesting work, but the idea that we could bring back something extinct is a false hope."