Cloned animals keep memories

Dolly is no longer alone

Two decades ago it was possible to clone an adult mammal for the first time. Companies are now doing this commercially; there are hundreds of cloned farm animals and pets around the world.

She would have turned twenty this summer: Dolly, sheep and scientific sensation. It was the first mammal to be successfully cloned from an adult cell of an adult mammal at the Roslin Institute in Scotland, and initially in camera: The birth of the small clone sheep was kept a secret until the researchers involved Had prepared a specialist publication. It wasn't until the end of February 1997 that it was published in the British journal Nature that Dolly's media breakthrough came. At that time she was already nine months old, a nearly full-grown sheep. She spent her whole life on the institute's farm, where she gave birth to six naturally conceived lambs. When she was five years old, she got headline-grabbing and for unknown reasons from arthritis; before her seventh birthday, she had to be put to sleep due to an incurable viral infection.

Around 20 species of mammals have now been cloned from adult cells, from house mice to camels to dogs and rhesus monkeys.

The Roslin Institute no longer clones farm animals; most of the researchers involved in the Dolly project now work for other institutions. The method itself has remained, more or less unchanged. What has changed, however, is the efficiency of the process - it is significantly higher today than it was in Dolly's time. At that time, the scientists fused 277 cells from a culture of udder cells from a six-year-old sheep with an egg cell from which they had previously removed the nucleus. Only 29 of these reconstructed embryos developed to the point where they could be used as surrogate mothers. A single living lamb was born - Dolly.

"Fifi" for the second

Nowadays, cloning is taking place all over the world, and Dolly has long ceased to be alone: ​​around twenty species of mammals have now been cloned from adult cells, from house mice to rats and camels to dogs, mules and rhesus monkeys. Even an extinct animal, the Iberian Ibex, was brought back to life with the dolly method - in the blink of an eye: the young animal died after birth. In fact, the complication rates during pregnancy and in the newborn animals are still higher, even after twenty years of cloning experience, than with conception under "normal" circumstances. However, if the clones survived both of them in good health, there is apparently little difference between them and their conspecifics created in a conventional manner.

Cloning has long since found its way out of science: today, both livestock and domestic animals are cloned commercially. The American company Viagen is a pioneer. It belongs to a biotechnology group that also owns Aqua Bounty Technologies - the company that produces the first food-approved genetically modified animal, a fast-growing (but not cloned) salmon. But you can also clone elsewhere. Nowhere is the process cheap; one should be prepared to invest tens of thousands to over a hundred thousand dollars.

How often these services are used, however, there are no precise figures. Reports speak of thousands of privately cloned animals. There are many reasons for the client. In the Missiplicity project launched in 1997, for example, it was the fear of losing a neutered mixed breed dog - called Missy - that prompted an American to promote dog cloning. The original Missy died in 2002. But today she's actually back, and in multiple versions.

However, if you expect to get your pet back one-to-one with all its characteristics and quirks, you will be disappointed. Because the clones are essentially similar to their "originals" - but less than identical twins. Because, unlike clones, they share a uterus, grow up together and thus have many similar experiences. Clone and "original", on the other hand, separate years and a multitude of different experiences and environmental influences. Even externally, a clone is not necessarily an identical copy of its "original". Special patterns or markings in the fur often arise spontaneously during development. This is impressively illustrated by the first successfully cloned cat: CC (Copy Cat). It is gray mackerel on white, but its "original" is a tortoiseshell cat: white with orange and dark spots. Nevertheless, there are apparently enough owners who do not want to accept the death of a beloved animal - and who are ready to instrumentalize their conspecifics for a copy of their favorite animal - after all, cloning requires egg "donors" and surrogate mothers.

In the case of a horse, unlike a dog or cat, the criterion for cloning is usually not a particularly close relationship with its owner, but an exceptional sports career. The process is interesting because it can be used to "transform" geldings (castrated male horses) back into fertile stallions. However, the method does not meet with enthusiasm everywhere: For example, the American Quarter Horse Association (AQHA), the world's largest horse breeding organization, has enforced in a multi-year legal process that it does not have to register cloned horses or their offspring in their stud books. That didn't stop the advocates of cloning from cloning a number of successful quarter horses and offering them for breeding. The sport horse clones are rarely used in sport. Because the performance of their “templates” is not only based on their genetic makeup, but also on a non-reproducible combination of environmental conditions. Polo ponies are an exception. Cloned horses can also be found on the field of play in this sport, which is bred using state-of-the-art methods anyway.

In the case of farm animals, primarily those that (or their offspring) bring particularly good "yields" - in terms of milk or meat - are reproduced. But the cattle breeders are also reluctant, at least in Europe. One expert calls the cloned animals a “look into the museum”. He uses milk production as an illustration, which can be traced back to the genes of both mother and father. This increases by an average of over a hundred liters every year, and the animals are becoming more productive from generation to generation. So why clone the parents when the offspring are more productive? In addition, a single bull can produce thousands and thousands of portions of semen - it is also unclear why this amount has to be doubled. According to the breeders, even a project in which researchers in the USA identified and cloned particularly valuable carcasses in slaughterhouses in order to then produce offspring with excellent meat quality with these clones is actually superfluous. Various methods can be used to determine the breeding value of a bull days after its birth. Not exactly, but good enough to eliminate the need to search for “clone-worthy” carcasses.

Morally questionable

But if the expected benefit of a cloned livestock or horse is assessed by many experts as low, how can it be justified that its production adversely affects the welfare of a number of its conspecifics? Not at all, as at least the EU Parliament decided last autumn. It wants to ban the production of farm animal clones in the EU. In order not to support them indirectly, the import of such animals, their offspring and the products of both into the EU should also be banned. Since clones cannot be genetically identified, this would require a pedigree for every imported farm animal or horse, from which it can be seen whether there are clones in its ancestral gallery. An ambitious goal that is still awaiting discussion in the Council of Ministers.

To outlaw the commercial cloning of livestock in this way would send a real signal. Morally, that would be justified - and not only with regard to useful animals, but also to domestic animals. Just because you can clone doesn't mean you have to. Livestock and horse breeding has come a long way without clones and continues to advance. Pets are dying. But aren't they worth mourning and remembering as individuals? Isn't the already doomed attempt to copy them in all their facets unfair to them and their clones? But cloning is a luxury and niche market and will probably remain so for the time being. That is why one can certainly ask oneself whether such far-reaching bans are really necessary. It would be nice if it could work without it.