[Science Scope] From Reading the Code of Life to Designing Genes

The CRISPR, Synthetic Embryo, and Organoid Revolution:
Moving Beyond "Treatment" into the Era of "Designing Life"
"Gattaca" Becomes Reality:
"Technical Capabilities Without Ethical Consensus Remain Dangerous"

The 1997 film "Gattaca" envisioned a future in which parents design their children’s destinies by selecting their genes before birth. In this society, the risks of heart disease, life expectancy, intelligence, and physical abilities can all be predicted through genetic information, allowing parents to choose healthier offspring. At the time, many dismissed it as far-fetched science fiction.

Yet, thirty years later, some of the film’s imaginations are gradually becoming reality. The CRISPR gene-editing technology has now reached the stage of treating inherited diseases in patients. Technologies for creating embryonic models that mimic the early development of human embryos using stem cells, as well as organoid technology, which creates tissues resembling human organs, are also advancing rapidly. The questions raised in the film are no longer just fiction.

The field of life sciences is undergoing a major turning point. Once focused on understanding the principles of life and treating diseases, science is now moving toward editing genes and recreating elements of life. Medical science is gradually shifting its focus from treating diseases after they develop to identifying and intervening in their causes beforehand.

Lee Daehee, Director of the Synthetic Biology Research Center at the Korea Research Institute of Bioscience and Biotechnology, explained, "For the past two decades, the main driving force of life sciences was 'reading,' as in decoding and observing the genome. Now, however, the focus has shifted to 'writing' and 'designing.' This is not just a matter of discourse, but a fundamental change in the way we conduct experiments every day."

So, how far has science actually come?

Editing Genes—Altering the Blueprint of Life

When the Human Genome Project was completed in 2003, scientists had succeeded in "reading" most of the genetic information contained in human DNA. This was the era of deciphering the code of life to discover the causes of diseases—an age of "reading life science."

Just a decade later, life science experienced yet another turning point. The advent of CRISPR gene-editing technology in 2012 enabled precise cutting and correction of DNA at desired locations. Subsequent technologies, like base editing—which substitutes a single nucleotide with exact precision—and prime editing—which inserts desired genetic information without making double-stranded DNA breaks—have further expanded accuracy and applicability.

Perhaps most importantly, these technologies are now entering real clinical settings. In November 2023, the United Kingdom became the first country in the world to approve a CRISPR-based therapy, Casgevy, and in December of the same year, the United States approved it for the treatment of sickle cell disease. The treatment involves extracting the patient’s blood stem cells, editing the genes outside the body, and reinfusing them back into the patient.

Sickle cell disease is a genetic disorder in which red blood cells become crescent-shaped, blocking blood vessels and causing severe pain. Gene-editing therapy changes the patient's cells to induce the production of healthy blood cells. This marks a shift from medicine simply managing lifelong symptoms to intervening directly in the genetic cause of disease.

Intracytoplasmic sperm injection (ICSI) used in in vitro fertilization (IVF) procedures. This image shows a sperm being directly injected into an egg using a micromanipulator. Photo by Ekem/Wikimedia Commons (Public Domain)

Jennifer Doudna, the UC Berkeley professor who developed CRISPR, warned, "The purpose of these discussions is not only to explain the science to the public, but to deeply consider how we move forward responsibly. It may take decades of research to fully understand how intended genetic changes affect the function of cells and embryos."

Going forward, the tasks ahead include developing “in vivo editing” technologies—directly correcting genes within the body—and expanding the range of treatable diseases. Editing a patient's cells outside their body is relatively easy for blood diseases but is much more challenging for organs such as the brain or heart, where cells are not easily extracted. As a result, delivering gene-editing tools accurately to target organs is a key to broader clinical application. Challenges also remain in the potential risks of unintended genetic changes and long-term side effects, as well as the high costs and limited accessibility of these treatments.

Constructing Parts of Life: From Embryos to Organs

Recently, life sciences have gone beyond editing genetic information and are now recreating the processes of human development and parts of organs in vitro. A prime example of this is the creation of embryonic models based on stem cells—so-called synthetic embryos.

In 2023, Professor Jacob Hanna’s research team at Israel's Weizmann Institute of Science succeeded in creating a human embryo-like model equivalent to a post-fertilization day-14 embryo using only stem cells, without sperm or eggs. These are not real embryos capable of developing into humans, but research tools for examining the “black box” of early stages such as implantation and embryonic development. These models hold the key to understanding repeated miscarriages and congenital disorders.

Professor Hanna explained, "An embryo is a self-organizing system. The goal is to provide appropriate cells so that the potential encoded within them is expressed." In other words, embryonic development is a process in which information inside cells and interactions between cells drive self-organization into tissues.

Organoids—structures resembling human organs created in vitro—fall within this same trend. Cultured from stem cells, organoids can partially reproduce the structures and functions of the brain, liver, and kidneys. Research is underway in which tumor organoids created from a cancer patient’s cells are exposed to various anticancer drugs to identify the most effective treatment.

Hans Clevers, a professor at Utrecht University in the Netherlands and a pioneer in organoid research, predicted, "Organoids are shifting into the field of personalized medicine, where drug candidates are tested and customized therapies are discovered for each individual patient."

Organoids can supplement animal experiments and increase the success rate of new drug development. By testing drug efficacy and toxicity on patient-derived tissues in advance, researchers can reduce trial and error. However, since organoids do not fully implement vascular, nervous, or immune systems, they are not yet ready to replace organs for direct transplantation. Both embryonic models and organoids are currently research tools for understanding disease and human development, rather than being an immediate clinical revolution.

Beyond Treatment to Design: Changing Goals in Medicine

This transformation indicates a paradigm shift in how medicine perceives disease. While 20th-century medicine focused on eliminating cancer cells or restoring damaged organs after the fact, today’s paradigm is shifting toward eliminating the cause of disease in advance or proactively intervening in the process of disease development.

Gene-editing tools now directly correct mutations driving disease; embryonic models reveal the very moments disease begins during early development; and organoids make it possible to test a patient’s cellular response to drugs in advance. Although these are different technologies, they share a common goal: early intervention in the process by which disease emerges.

Notably, the convergence of synthetic biology and artificial intelligence (AI) is accelerating these trends. Scientists now design genetic circuits or proteins by computer, synthesize DNA to implement them in cells, and use AI to analyze data and improve their designs. Research is no longer limited to observing natural phenomena but is moving toward creating cells and biological systems with desired functions.

Various human embryo models created using stem cells. These research models replicate the early developmental stages of human embryos without the fertilization of sperm and eggs, and are used to study the causes of implantation, recurrent miscarriage, and congenital diseases. They are not embryos capable of developing into actual humans. Provided by Monash University/Nature

Whereas researchers used to alter one gene at a time and wait for results, now countless designs can be generated simultaneously, and automated experiments and AI analysis make it possible to rapidly discover better outcomes.

Of course, designing life does not mean that appearance or intelligence can be manipulated at will. Complex traits are determined by myriad genetic and environmental factors, and current research is squarely focused on treating serious genetic disorders. Still, it is impossible to avoid questions about where to draw the line between “treatment” aimed at restoring normal function and “enhancement” designed to increase ability.

'Can Do' Does Not Mean 'Should Do'

In 2018, when the Chinese scientist He Jiankui edited the genes of human embryos using CRISPR technology and brought twins to term, the scientific community responded not with applause but with fierce criticism. This was because he forcibly implemented germline editing, which is inherited by the next generation, without established safety standards. He ultimately received a prison sentence from the court.

The World Health Organization (WHO) has stated, "At this stage, the clinical application of human germline genome editing is irresponsible" and recommended a ban. The “14-day rule,” which restricts culturing embryos to 14 days after fertilization, is once again under debate as advances in embryonic modeling technologies challenge its relevance. The 14th day marks the appearance of the “primitive streak,” the basic axis of the body in the embryo. As technology now allows researchers to surpass this threshold, discussions have begun over whether the existing benchmark should still be maintained.

Brain organoids pose new questions as well. Although current brain organoids are much simpler than an actual human brain, as the connections and responses of neurons become more complex, many are calling for proactive discussion of when such organoids should be considered ethically protected entities.

Director Lee emphasized, "The line between what is technically possible and what is socially acceptable is a ‘moving boundary’ set by social consensus. Just because we can do something does not automatically justify that we should do it."

How Far Will Humanity Go in Designing Life?

In the twenty-first century, life science is expanding from understanding the principles of life to technologies that directly intervene in and design biological functions. While humanity has opened the door to treating rare genetic disorders and personalized precision medicine, we also shoulder the risks of potential misuse.

As our ability to design genes and proteins with AI grows, the risk of misuse—such as creating dangerous pathogens—also increases. This is why safeguards must be implemented, such as screening out dangerous genetic information during DNA synthesis and reviewing the potential for misuse throughout the research process.

But simply blocking technological advancement is not the answer. Excessive regulation may hamper the treatment of rare diseases and drug development, while pushing ahead recklessly with technological promises alone could lead to irreversible consequences.

What is needed is an approach that integrates safety and responsibility into research design from the outset. As our capacity to design life grows, our social capacity to control these technologies must grow with it.

The future portrayed by the film "Gattaca" has yet to arrive. But the choices surrounding that future have already begun. How far will humanity go in using the technology it has created for itself?

This content was produced with the assistance of AI translation services.