The United States has launched a cloning service that can "bring pets back from the dead," but is the new animal really your former beloved pet?

Recently, Tom Brady, a retired American football star, has sparked a public outcry. However, this time, what caught people's attention was not his football skills but his dog.

On November 4th, the biotech company Colossal Biosciences issued a statement. In the statement, Brady revealed that his current Pit Bull, Junie, was "replicated" through the company's cloning service. Junie's predecessor was Lua, which he co - raised with his ex - wife and died in 2023.

A photo of Brady with Lua (left) and Junnie (right); Brady is one of the investors in Colossal Biosciences (Photo source: Instagram)

As soon as the news broke, different opinions emerged. Supporters of Brady said that cloning service is a new way to cope with the death of a beloved pet. Opponents, however, sneered that the cloned animal is fundamentally different from the original one, and it's just a self - indulgent act of self - deception by the wealthy.

So, what is the truth about the pet cloning service?

What brought Brady's beloved dog "back to life" is a technology called "somatic cell nuclear transfer". Somatic cell nuclear transfer is not mysterious at all. As early as 1996, scientists used this method to create the cloned sheep Dolly. We can roughly simplify it into three steps.

Dolly was the first mammal cloned by humans using somatic cell nuclear transfer technology. Its specimen is currently on display at the National Museum of Scotland (Photo source: Wikipedia by Toni Barros)

Step one: Extract somatic cells (skin, ear, fat, etc.) from the animal to be cloned, and then remove the nucleus of the somatic cell. The nucleus is the key to the whole cloning process because it contains almost all the genetic information of the individual and has the full potential to guide the individual's development.

Step two: Find an oocyte and remove its nucleus. Generally speaking, the oocyte is preferably from the same species as the animal to be cloned, which can increase the success rate of cloning.

Step three: Put the extracted nucleus into the enucleated oocyte to form a reconstructed egg. When the reconstructed egg is activated and divides into an embryo, it can be placed in the surrogate animal. Then, you can wait for the cloned animal to be born.

Schematic diagram of the somatic cell nuclear transfer process (Photo source: Wikipedia)

The company's official website shows that they currently only offer cloning services for cats and dogs. The cloning time is approximately 1 month for the cultivation of the reconstructed egg + 2 months for pregnancy + 2 months for lactation. As for the cost, it costs $1,600 to preserve the genes, and the cloning fee is $50,000 (equivalent to about 11,000 yuan and 360,000 yuan respectively).

For many people who want to learn about this service, the most concerning question is probably: Is the newly obtained animal really the same as the previous beloved pet? Can they seamlessly return to the old way of getting along, just as the company's official website describes, "Let love never say goodbye" and "Bring the pet back to life".

Viagen, which holds the patent for somatic cell nuclear transfer technology, is now a subsidiary of Colossal Biosciences (Photo source: Internet)

If you have the above - mentioned ideas, you are likely to be disappointed because cloning cannot replicate the personality. It just creates a twin of your pet. That is to say, even if Brady's cloned dog Junie looks exactly the same as the previous Lua, it is impossible to replicate the way Lua got along with its owner, let alone have the previous memories.

Moreover, no one can guarantee that the cloned animal is 100% identical to the original one. This is mainly because the mitochondrial DNA of the reconstructed egg comes from the enucleated oocyte. In addition, acquired factors such as diet, stress, and exercise may also affect gene expression, resulting in different appearances.

From this perspective, the huge slogans on the pet cloning website are just a marketing strategy, creating a warm - hearted filter to deceive the eyes of pet lovers.

(Photo source: Pickpik)

Beyond the marketing talk, the ethical issues in the cloning process are also the main targets of criticism. First of all, the success rate of cloning technology is still relatively low at present. Taking dogs as an example, it is only about 4%. This means that if you want to successfully give birth to a cloned puppy, the staff needs to prepare at least 25 oocytes.

Based on the data of all species, even if the cloned individual survives the pregnancy, nearly half of them will die at birth or within the first month.

It is conceivable that, for safety, commercial institutions are likely to cultivate multiple cloned individuals at the same time. Then, which one to deliver to the customer and how to deal with the redundant animals are also problems. However, research has found that when the cloned individual reaches one month old, its physical condition is not significantly different from that of a normal individual, and their offspring are also healthy.

CC, the world's first cloned cat, was born in 2001 and died in 2020 (Photo source: Wikipedia)

The high failure rate of cloning is also a nightmare for surrogate animals. Some studies have pointed out that surrogate animals carrying cloned embryos have a higher probability of miscarriage, difficult labor, abnormal placenta, and cesarean section. Many surrogate animals show anxiety and pain because of this, and some even lose their fertility directly.

Of course, cloning is not completely useless.

For example, humans can use it to continue the genes of excellent working dog breeds. In the field of animal protection, somatic cell nuclear transfer can rapidly increase the number of endangered species. Even if consumers simply want a new animal that looks exactly the same as their previous beloved pet, it is understandable.

Colossal Biosciences has also launched an "anti - extinction" project, planning to use gene - editing tools and somatic cell nuclear transfer technology to revive extinct species. Skeptics point out that in essence, this is just creating a close - relative species that looks like the extinct one. (Photo source: Colossal Biosciences)

However, for many pet owners, the happiness lies in the process of gradually building a connection with the pet, in the dog waiting at the door to warmly welcome you after recognizing your footsteps, in the cat going from being cold and aloof at first to showing its belly in front of you trustingly...

These are all unique memories we have with a specific individual, and these memories cannot be forcibly transferred to another individual.

As animal rights activist Ingrid Newkirk said, if you really want a new pet, why not choose to adopt? Give another life a chance to survive and give yourself the possibility of establishing a new emotional connection.

References

[1]https://www.nytimes.com/2025/11/04/science/tom-brady-dog-cloning.html

[2]https://www.biomart.cn/lab-web/method/31idqkqgo26un.html

[3]https://curis.ku.dk/ws/files/245670445/s12876_020_01356_2.pdf

This article is from the WeChat official account "Bring Science Home" (ID: steamforkids). Author: Liu Liuqi, Proofreader: Ziv. It is published by 36Kr with authorization.