CRISPR gene editing: how it works It is a topic that raises real expectations today, not just scientific fantasies.

In this article you will find a summary clear:

First, the historical context and molecular basis; second, the operating mechanisms and variants; third, current applications in health and agriculture; fourth, risks and ethical debates; and finally, the situation in Mexico and its projections.

Rather than presenting isolated theory, you'll understand what's already being done, what's missing, and how it could affect your life or your environment.

Have you ever wondered how “molecular scissors” can precisely change a gene?

Origin and molecular basis

In 2012–2013, the groups of Jennifer Doudna and Emmanuelle Charpentier described how the CRISPR-Cas9 system could be used to precisely edit genomes, based on a bacterial defense mechanism.

Since then, that idea has evolved rapidly.

The system essentially involves two components: a guide RNA (gRNA) that recognizes the region of DNA to be edited, and a Cas protein (such as Cas9) that cuts the double strand of DNA.

After the cut, cells activate their own repair mechanisms (NHEJ or HDR), which can be used to insert, delete or replace specific sequences.

A relevant fact: editing costs have dropped dramatically, which has expanded its use in university labs and startups with moderate resources.

To visualize this better, imagine DNA as a two-lane highway (two strands).

The gRNA points to a specific spot, the Cas protein acts as a selective removal in that section, and then the internal repair workers They rebuild the asphalt, sometimes with planned variations.

How does CRISPR gene editing work?

Here lies the core of CRISPR gene editing: how it worksThe process can be divided into several stages:

Guide RNA (gRNA) design

A specific sequence of the target genome (approximately 20 nucleotides) is chosen that precedes a PAM (“Protospacer Adjacent Motif”) site.

That sequence will guide the system to cut exactly there.

DNA cutting by the Cas protein

The Cas protein (e.g., Cas9) binds the gRNA complex and positions itself on the DNA. If the match is good and the appropriate PAM is found, Cas9 cuts both strands of the DNA.

DNA repair

This is where cellular mechanisms come in:

• NHEJ (non-homogeneous end joining): Joins broken ends quickly, but introduces errors (deletions/insertions).
• HDR (homologous directed recombination)If a DNA template is provided, the cell can use it to repair the region with the desired modification.

Improved variants

There are safer versions such as base editing (change a base without breaking both strands) and prime editing (using a template RNA that directs more precise insertions/deletions), with a lower risk of off-target effects.

Current applications: health, agriculture and biotechnology

Medicine and gene therapies

CRISPR editing is already being tested in clinical trials to treat genetically based diseases, such as certain types of inherited blindness and blood disorders.

Ways are being sought to safely introduce the system into human cells (via adeno-associated viruses or nanoparticles).

For example, a patient with a point mutation in a liver enzyme could receive ex vivo edited cells that correct the defect and then reintroduce them.

Its use is also being explored in cancer therapies: editing immune system cells (such as T lymphocytes) to improve their ability to recognize and attack tumors.

Agriculture and plant breeding

CRISPR gene editing: how it works It is essential to understanding these agricultural advances: genes have already been edited in corn for drought tolerance, pest resistance, or yield modification.

In Mexico, CINVESTAV uses CRISPR-Cas to modify genes like ZmTMS5 to induce male sterility in hybrid corn lines, optimizing production.

In plantations, the system can be introduced by Agrobacterium, biolistics or protoplasts.

Researchers then select plants that retain only the desired modification, with no additional traces of the CRISPR tool.

Industrial biotechnology

CRISPR allows microbial organisms (bacteria, yeast) to be modified to produce pharmaceutical compounds, biofuels, or biomaterials.

For example, adjusting metabolic pathways so that yeast produces more renewable carbon bioplastics.

Risks, limits and ethical debates

Off-target effects

Although RNA guides increase specificity, there is always a risk of off-target cuts. That's why robust validation systems are essential in every project.

Germline vs. somatic editing

Somatic editing (in non-reproductive tissues) does not transmit changes to the next generation and is more accepted.

Germline editing (in gametes or embryos) generates hereditary effects and raises major ethical dilemmas: who decides which trait to correct or “enhance”?

Unequal access and genetic discrimination

If only certain groups can access CRISPR therapies, health inequalities could worsen. There is also a risk of discrimination due to misused genomic data.

Regulations, governance and security

Many countries lack specific laws on gene editing.

In Mexico, the UNAM recently created a Gene Editing and Cryopreservation Unit (UEGC) to serve researchers, which represents a step towards clearer institutional regulation.

Furthermore, the legal loophole is slowing down agricultural implementation in Mexico; some scientists are already drawing attention to this legislative paralysis.

Situation in Mexico and future prospects

National scientific infrastructure

UNAM's UEGC is a pioneer in Mexico and Central America in supporting research that requires the generation of gene-edited animal models.

In the plant field, although there has been progress in CRISPR trials with corn and other crops, agricultural laws restrict the commercial release of edited varieties outside the laboratory.

Outstanding Mexican Scientists

Researchers such as Gloria Soberón Chávez, an expert in molecular genetics, bring credibility to the Mexican scientific ecosystem.

Besides, Luis Rafael Herrera Estrella has been a pioneer in plant genetics in Mexico, contributing to resistant varieties in crops.

Challenges and goals to achieve

For the public to trust CRISPR gene editing: how it works, transparency, citizen participation and solid regulatory frameworks are required.

Approved therapies using CRISPR to correct single-gene diseases, as well as climate-change-resistant edited crops, are expected to emerge in the next decade.

It is also feasible for Mexico to regulate and promote domestic innovation, positioning itself among the Latin American leaders in biotechnology.

Comparative table of CRISPR variants and applications

Variant / aspect	Main feature	Featured Apps
Traditional CRISPR-Cas9	Double-stranded cleavage with gRNA	Clinical trials, basic plant-based editing
Base editing	Timely change without breaking both strands	Correct single-base mutations
Prime editing	Precise insertions/deletions with RNA template	More controlled and secure editions
Delivery system	Viral plasmids, nanoparticles	Human therapies, cell culture
Validation / control	High-throughput sequencing	Minimize off-targets, post-use monitoring

Read more: Most frequently asked questions in interviews

Conclusion

Grasp CRISPR gene editing: how it works It is not a technical sacrifice: it is citizen empowerment.

Gene editing is no longer just laboratory research; it can now shape the health, nutrition, and medicine of the future.

But its promise depends on clear standards, ethical oversight, and equitable access.

The balance between innovation and prudence will determine whether CRISPR becomes an instrument of well-being or a source of controversy.

You, as an informed reader, play a key role in demanding transparency and responsibly benefiting from these incredible advances.

Read more: Advances in biotechnology: what genetics promises

Frequently Asked Questions (FAQ)

How many cells must be edited to achieve a therapeutic effect?
It depends on the tissue: in organs like the liver, a few tens or hundreds of thousands are enough, if you can get them to proliferate efficiently.

Can a failed CRISPR edit be reversed?
In theory, through new editions or repair mechanisms, but this operation adds complexity and risk.

Thanks to CRISPR, are genetically edited crops already being marketed in Mexico?
So far, not on a commercial scale: the regulatory framework does not allow for the immediate release of CRISPR-modified crops outside the laboratory.

How big is the off-target risk?
In controlled trials, these risks are typically low (less than 1 % of detectable extra cuts if the design is careful), but each application requires validation.

Can CRISPR be used in adult humans with acquired diseases?
Yes, ex vivo therapies (editing cells outside the body and reinjecting them) are being explored for blood disorders, immune disorders, and cancer.