Exeter, Devon UK • Jul 18, 2024 • VOL XII

Exeter, Devon UK • [date-today] • VOL XII
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Designer Genes

5 mins read
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The National Academy of Sciences (NAS) has given a free pass to a DNA editing tool to alter the human genome.

This opens the way to unprecedented control over the human genome, and the possibility to prevent, or even cure, genetic diseases.

Back in 2012 Professor Jennifer Doudna and her colleagues were spending long hours in their lab at University of California, Berkeley (pictured above), perfecting the so-called CRISPR/Cas9 system. Not long before, they were conducting studies looking at how bacteria defend against viruses.

Drawing upon more than a decade of research on the CRISPR immune adaptive system in bacteria, they developed CRISPR-Cas9, a new technology for gene editing.

“CRISPR allows the modification of genes at specific locations with precision and can be applied to any species”

Unlike previous methods, CRISPR allows the modification of genes at specific locations with precision and can be applied to edit the DNA of any species. Just like a missile, enzyme Cas 9 breaks down the DNA strands at specific locations. It does so by binding to a predesigned sequence of RNA search string which guides it to the target location in the genome. Once it reaches its destination, the enzyme makes a cut across the DNA at that site. The break is immediately detected, and a host of processes are initiated to repair the broken strand. As a result, a new sequence is synthesized that replaces the original piece of DNA at the site of the cut.

The discovery was met with tremendous excitement. Soon after, scientists around the world started using the technology for different purposes.

Some used CRISPR/Cas 9 to repair flawed DNA in mice. And they have done so successfully.  Others used the technology to breed enhanced crops.

Last year, Chinese scientists at Sichuan University injected edited immune cells directly into a patient in an attempt to cure metastatic lung cancer. They disabled the gene codes for a protein which stops an immune response. A number of oncologists have praised the rationale, expecting the edited cells will attack cancer and prevent it from proliferating.

A turning point followed when researchers at Karolinska Institute in Stockholm publicly acknowledged using Crispr/Cas9 to insert edited genes into healthy human embryos. This was done in an attempt to devise infertility treatments that would help prevent infertility.

a schematic of DNA and two spanners labelled CRISPR

Image: Wikimedia Commons

However, in a NPR report they have been clear in saying that the embryo will be allowed to survive for 14 days at the most. This means that it would not be implanted into a woman’s womb and develop into a baby.

This breakthrough took the world by storm. On one hand, it shows that Crispr/Cas9 holds immense promise in treating a range of medical diseases that have a genetic component. Yet, these advances are not without ethical ramifications.

Some fear that targeted mutations to the human embryo may go beyond fixing broken genes, to enhancing them beyond their natural function.

One may want to manipulate genes to carry desirable features such as enhanced intelligence and better bones, for instance. Others may want to use Crispr-based therapies to prevent aging.

Can we be forgiven for seeing a dystopian world of genetically engineered human beings on the horizon?

“these advances are not without ethical ramifications”

Most likely not.

In a report published last Tuesday, NAS gave permission for genome editing research to proceed only if it contributes to preventing disease or disabilities. They believe that human genome editing is justified when medicine does not offer a “reasonable alternative”. Besides, they have shown scepticism in the ability of this technology to go beyond repairing defects.

For now, designer babies have received a resounding no. However, we have to wait and see what regulatory agencies have to say in response to their definitions of “prevention” and “enhancement.”

However, one thing is clear. Once the subject of science fiction stories, human genome editing has now begun, in and out of the public eye, and it has the potential to pave the way for a new era of genetic disease prevention.

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