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How Dolly Revolutionized Cloning and What Happened Next

What if you could create an exact copy of yourself?


¿Quién fue la oveja Dolly?

Reproductive cloning, a concept once confined to science fiction, became a reality when the sheep Dolly was introduced to the world in 1996. Dolly not only pushed the boundaries of science and biology but also sparked a whirlwind of debate about the possibilities and limitations of cloning.


In this article, we’ll explore the evolution of reproductive cloning, from early frog experiments in the 1950s to more recent developments like cloning dogs and primates, and discuss the ethical and scientific implications of these technologies.


From Frogs to Dolly


The first cloning in the animal world was achieved in 1952 when scientists Robert Briggs and Thomas J. King successfully cloned frogs using nuclear transfer. Though rudimentary by today's standards, these early experiments laid the groundwork for future cloning.


These initial efforts, although modest, demonstrated that cloning was not just a fantasy but a developing scientific possibility.


¿Cuál fue el primer animal clonado?

The true revolution came in 1996 with the birth of Dolly, the cloned sheep from the Roslin Institute in Scotland.


Dolly wasn’t just any sheep; she was the first of her species to be cloned from an adult somatic cell using a technique known as somatic cell nuclear transfer (SCNT). This process involved inserting the nucleus of a cell from an adult sheep’s udder into an egg cell that had its original nucleus removed.


¿Quién era Dolly?

The surprise and wonder of the experiment weren’t just due to the technical success, but also the possibility of reprogramming adult cells to develop a complete organism, challenging previous beliefs about cell differentiation.


Dolly’s birth caused a huge stir, as it demonstrated that creating a genetic copy of an adult being was possible, a concept previously considered impossible.


However, subsequent studies revealed that Dolly had shortened telomeres, a sign of premature aging, which helped explain her death at age six. This finding raised serious questions about the health and longevity of clones and stimulated further research into the long-term effects of cloning.


Since then, cloning has advanced significantly, and Dolly’s story remains a source of excitement and controversy in the field of biotechnology. Her legacy has deepened our understanding of life itself.


Somatic Cell Nuclear Transfer (SCNT) Methodology


Reproductive cloning, the technique behind Dolly's creation, is based on a complex process known as somatic cell nuclear transfer (SCNT). While it might sound complicated, the essence of the method is quite intriguing.


How Does Somatic Cell Nuclear Transfer Work? 


In simple terms, the technique involves taking the nucleus from an adult cell, which contains the complete DNA of the organism we want to clone, and introducing it into an egg cell that has had its own nucleus removed (enucleated egg).

It’s like taking the "brain" of a cell and placing it into an "empty egg" to start developing a new organism.

Here’s the step-by-step process:

  1. Nucleus Extraction: First, scientists obtain a cell from the organism to be cloned. This cell contains the DNA that will determine the characteristics of the new organism.

  2. Egg Preparation: Next, the nucleus is removed from an egg, leaving it empty and ready to receive a new nucleus.

  3. Fusion and Stimulation: The nucleus from the donor cell is inserted into the enucleated egg. The egg, now with the donor cell's nucleus, is stimulated to start dividing and form an embryo.

  4. Implantation: Finally, this embryo is implanted into a surrogate uterus, where it will grow into a complete organism.


    Despite advances, this technique remains challenging. For example, Dolly was created after manipulating 277 eggs, with only one resulting in a successful birth, highlighting the complexity of the process.


Why Is It Important?


Somatic cell nuclear transfer has not only allowed for animal cloning but has also opened up new possibilities in biomedical research, such as creating more accurate experimental models and developing personalized medical treatments.


Scientific and Ethical Implications of Reproductive Cloning


Dolly’s impact in 1996 was a milestone that resonated worldwide, and her success inspired a series of experiments with other species (pigs, horses, cows…).


In the 2000s, cloning expanded to producing animals with specific genetic traits. In Argentina, cows were cloned to produce milk with human proteins, a breakthrough that sparked controversy with "transgenic cows" over food safety and ethical concerns about manipulating animal genetics for human benefit.

Vaca transgénica argentina produce insulina

In 2005, the birth of Snuppy, the first cloned dog, also occurred. This experiment by South Korean veterinarian Hwang Woo Suk required the implantation of over 1,000 cloned embryos into 123 surrogate mothers, with only three achieving a successful pregnancy.


Snuppy sparked debates about replicating our animal companions and raised ethical questions about playing "god" with life.añeros animales y planteó cuestiones sobre la ética y jugar a ser "dioses" con la vida.


Snuppy el perro coreano clonado

More recently, in 2018, Chinese scientists successfully cloned two Rhesus monkeys, Zhong Zhong and Hua Hua, marking a significant step toward cloning primates and potentially humans due to our high genetic similarity.


Conan and the Rhesus Monkeys: Cloning in the Last Decade


In 2018, Chinese scientists made significant progress by cloning two Rhesus monkeys, Zhong Zhong and Hua Hua, using SCNT and a technique involving modification of the placenta’s trophoblasts. This modification improved the viability of cloned embryos, ensuring an optimal environment for embryo development and could be key to advancing and perfecting cloning.


The achievement of Zhong Zhong and Hua Hua brings human cloning closer while being used for deeper studies on human diseases and potential advances in personalized medicine.

Monos de Rheus Chinos clonados

The story of Conan, the cloned dog of Argentine President Javier Milei, also began in 2018 but gained widespread attention in 2023. Conan is one of five puppies cloned from the president’s deceased dog, showcasing the growing interest and accessibility of companion animal cloning services, though the process remains complex, expensive, and with a relatively low success rate.

Milei, presidente de Argentina, posando con los clones de su perro Conan

Commercializing cloning technology for emotional purposes is controversial. While the idea of bringing back your four-legged friend may be appealing, it also raises questions about the ethics of intervening in nature for commercial gain.


Human Reproductive Cloning: Potential and Ethical Limits


Human reproductive cloning has been and remains one of the most controversial and debated topics in biotechnology. While therapeutic cloning, involving the creation of stem cells for treating diseases, is accepted in many countries (under strict regulations), reproductive cloning remains a highly controversial and widely banned area.


The concept of cloning a human raises profound and complex questions about identity, ethics, and the limits of science. In 2008, the biotechnology company Stemagen conducted an experiment that generated cloned human embryos up to the blastocyst stage, but these embryos were destroyed before they could be implanted.


¿Cómo se hace una clonación?

This attempt provoked a wave of criticism and skepticism. Many experts and global organizations questioned not only the biological risks and potential health complications but also the moral and social implications of replicating humans.


Despite these issues, the discussion on human cloning remains active in the scientific and ethical community. Some argue that cloning could offer new opportunities for medical research and resolving genetic diseases, while others see the potential dangers of playing god and the unpredictable consequences of manipulating human life at this level.


Applications of Cloning in Modern Medicine: Pharmacogenomics and Personalized Genetics


Cloning has not only advanced in basic biotechnology but is also beginning to show its potential in modern medicine. In particular, cloning in fields like pharmacogenomics and personalized genetics is revolutionizing how we understand and treat diseases.


Pharmacogenomics greatly benefits from advances in cloning. By creating genetically identical animal models, scientists can investigate how different individuals respond to specific drugs, facilitating the development of more effective and personalized treatments.

These models allow for the study of genetic variations and their influence on drug efficacy and safety, improving the precision of therapies.


Cloning also holds promising implications for personalized medicine. The ability to clone specific cells or tissues from a patient opens possibilities for tailor-made therapies.

For instance, cloning stem cells could facilitate the creation of compatible tissues for transplants, minimizing rejection risks and optimizing treatment success.


Advances in cloning are rapidly transforming medicine. They enable research on rare genetic diseases and the personalization of treatments to meet each patient’s individual needs.


In this new context, understanding genomic data precisely becomes essential to ensure that new therapies are both effective and safe.


This is where Matchgénica helps by interpreting complex genetic data, assisting medical professionals in personalizing treatments and improving patient care without needing to be a genetics expert.


¿Por qué clonar?

Now that we’ve seen how cloning has moved beyond science fiction and is becoming a more tangible reality, it’s clear that dialogue and education about these advances will be crucial for the ethical and safe development of this branch of science.


If you're interested in learning more about your DNA, you might want to explore dark DNA or what's happening with synthetic DNA.

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