Imagine the ability to regenerate a lost limb from a car accident or rejuvenate your organs after a heart attack — the solution: Clones.
Over 25 years ago, the ethical debate began with the first cloned mammal in 1996. It opened many possible opportunities and raised even more controversial questions. However, as cloning advances, the quest for the scientific foundation of youth could unlock the secrets to immortality.
The path to a duplicate
Clones occur in nature. Single-celled organisms and some plants clone themselves as a form of asexual reproduction, meaning only one parent is required to create a new individual. However, animals need two sets of chromosomes for reproduction. Therefore, natural human clones occur as identical twins.
The cloning begins with a mature somatic cell containing both sets of parental DNA, such as a skin or muscle cell. Reproductive cells, like sperm, cannot be used. Next, an egg cell is extracted from a female donor of the same species. The DNA-containing nucleus is removed from the egg cell to prepare for the new DNA. The new nucleus from the chosen somatic cell is injected into or fused into the egg cell. This egg cell divides and grows into a blastocyst – a rapidly dividing ball of cells. The blastocyst is developed as a lab culture, then transferred into a foster mother of the same or similar species.
The first of its kind
Dolly, a Finn Dorset sheep, was the first cloned mammal from an adult cell. Previously, cloned sleep began with embryo cells instead of developed somatic cells. Her birth proved that stem cells could create copies of animals. Since then, other animals, such as endangered species, have been successfully cloned with this process.
Unfortunately, Dolly passed away in 2003, only at the age of six, from lung tumors. The average lifespan of a domestic sheep is 10 to 12 years. DNA analysis showed this sheep expressed shortened telomeres — protected ‘caps’ at the end of DNA that tend to change with age. Her caretakers questioned if Dolly was ‘older’ than she seemed due to her donated adult DNA.
Dolly raised the debate on the ethics of clones yet opened endless possibilities for future biological and medical applications of this revolutionary technique.
The root of the controversy
Stem cells are the raw materials of the body. They can generate any specialized cell for any given function. These special human cells are at the root of regeneration opportunities yet shape the controversial path of cloning technologies.
Simply put: reviving stem cells destroys embryos. Many oppose this research for this fact alone. Embryos are the early developmental phase of an animal; in humans, this is the case until it is considered a fetus at eight weeks from conception. Since it is illegal to create embryos for stem cell research, most are donated, with consent, from in-vitro fertilization clinics. Furthermore, embryonic stem cells are found at the blastocyst stage, which only occurs in the first few days of fertilization.
Adult stem cells are not as viable as their embryonic counterparts because they cannot create any cell type and can contain abnormalities from their environment. Nevertheless, researchers continue to learn more about their potential use.
After the Supreme Court overturned Roe. v. Wade in June 2022, recent abortion laws threaten embryonic stem cell research. Though these laws are aimed at abortion, there are many downstream consequences if embryos and fetuses gain the same personhood rights.
The courts will be the battlegrounds for these long-debated ethical questions — but at what cost? Many gene and therapeutic products in the pharmaceutical pipeline are developed with stem cells. But, unfortunately, few are currently available to the public. Yet, the potential is untold.
The Human Market
Each day, 17 people die waiting for an organ transplant – mostly kidney patients. Unfortunately, the demand for organs still does not match the supply. According to Global Database on Donation and Transplantation, illegal organ trafficking generates approximately $840 million to $1.7 billion annually, leading to a dehumanizing trade in body parts. Cloning organs could be the solution.
Cloning one’s cells to treat and cure a disease eliminates the risk of introducing foreign cells and the possible rejection of the treatment. Therapeutic cloning treatments have been possible in mice for Parkinson’s disease, for example, as well as with other species, but not yet in humans. However, other stem cell treatments, such as regenerative medicine to repair damaged tissues and stem cell transplants for cancer patients, are successful.
Additionally, some 185,000 amputations occur each year in the United States alone. Could cloning technologies be used to replicate limbs too? Other species can naturally regenerate limbs by reverting their cells to stem cells. Maybe they hold the key to cellular regeneration in humans.
On the brink of immortality
Altos Labs is a new biotechnology company funded by billionaire Jeff Bezos. Their goal is not immortality per se but cellular rejuvenation therapies to reverse disease, injury, and disability that occur throughout life. Age is the biggest risk for disease. This scientific foundation of youth will help people live longer, healthier lives.
In 2016, the Salk Institute, led by now Altos researcher Juan Carlos Izpisua Belmonte, reversed aging in mice and increased their lifespan by 30 percent. The researchers used cellular reprogramming, which reverted some cells to an embryonic state, allowing the cells to become young once more. The incredible medical applications of this research cannot be denied.
“We can program and rejuvenate the tissues and organs of animals with different pathologies [diseases], as well as rejuvenate their cells,” explains Izpisua to El Pais. “Conceptually, I find no reason that stops us from thinking that similar results cannot be achieved in humans, both with respect to improving the course of many diseases and with the rise in the length and quality of life.”