Photo: Reuters
Photo: Reuters

OPINION: Is gene editing the beginning of a slippery slope?

By Louis Fourie Time of article published Aug 23, 2019

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JOHANNESBURG - Although many people mistakenly think that the Fourth Industrial Revolution (4IR) mainly entails a digital transformation, it is much more comprehensive. The 4IR is driven by the confluence of physical, digital and biological technologies that are completely changing the societal fabric of our times in ways that were previously inconceivable.

One of the fields that have a major impact on the 4IR is biomedical engineering. Biomedical engineering is a relatively new, interdisciplinary field of medicine, biological science, and engineering with the basic aim of improving human health.

Research in this field covers innovative prosthetic limbs, medicine delivery technology, tissue and stem cell research, genetic engineering, biomedical signal processing and many other technologies focused on improving human health. These technologies not only improve our health and lives, but are also subtly restructuring the way we live.

The late Nobel laureate Sydney Brenner once said: “The big lesson to learn here is that in science, only mathematics is the art of the perfect. Physics is the art of the optimal, and biology is the art of the satisfactory: if it works, you keep it; if it doesn't, you get rid of it.”

The problem is that in the thinking of the modern human being “satisfactory” is no longer good enough. According to Brenner, humans have given up evolving by biology alone. With new scientific tools such as CRISPR-Cas9 gene editing, scientists are able to reshape genomes and alter biological form and function of human beings.

Due to the ease of use and affordability of the CRISPR-Cas9 technique the pursuit of human perfection through gene editing has already begun.

But first let us clarify the remarkable gene-editing tool CRISPR-Cas9. CRISPR (Clustered Regularly Interspace Short Palindromic Repeats) is found in the genomes of bacteria and other micro-organisms.

When the threat of a virus arises, the bacteria use the CRISPR immune system to identify and destroy the viral genome.

Over time scientists have adapted this system so that it could be used to alter the genome of any organism, including humans.

Cas9 is an enzyme and its work can best be described as a pair of “molecular scissors”. In the most common form of CRISPR, Cas-9 is used to cut out selected sections of DNA or add new sections to the existing DNA. A guide molecule is programmed to guide the enzyme exactly where it has to cut in the DNA sequence.

The CRISPR-Cas9 DNA editing technique thus works like a biological version of the very familiar “find and replace” function of word processing software by finding and replacing a defective strand of human DNA with a healthy copy.

It was used for the first time on a human on October 28, 2015, when oncologist Dr Lu You from Sichuan University in Chengdu transplanted modified cells into a patient with aggressive lung cancer with the aim of attacking and defeating the cancer.

CRISPR-Cas9 could have huge benefits for human development in future, with the potential to treat inherited genetic defects and several cancers, as well as eradicate diseases.

Over the last few years, significant progress has been made with life threatening diseases such as cancer, HIV/Aids, diabetes, coronary heart disease, severe obesity and inherited high cholesterol.

A group of people was found in Texas, US, on whom a high-fat, high-sugar diet had no effect due to genetic mutation. Their cholesterol level was 30 to 40percent lower than the rest of the population.

Scientists used CRISPR to successfully introduce the mutation into the DNA of test subjects with the result of an immediate 40percent decrease in cholesterol.

However, many scientists over the years expressed their fears that the CRISPR technique could be used to create “designer babies”, which would be ethically problematic and would also carry high risk. In November 2018, the Chinese scientist He Jiankui from the Southern University of Science and Technology in Shenzen drew a lot of attention when he claimed to have created the world’s first gene-edited babies. The team eliminated the CCR5 gene in embryos of seven couples before they were transferred into the mother’s uterus to render a child resistant to HIV. The first genetically modified babies to be born were the twins Lulu and Nana, according to He Jiankui.

As is understandable, these developments entail serious ethical challenges and therefore received critique from all over the world, as well as calls for a global moratorium on heritable gene editing. The technology is ethically charged because any change to an embryo (stem cells) would be inherited by future generations and could eventually affect the entire gene pool and future of the human race.

According to Fyodor Urnov, associate director of the Altius Institute for Biomedical Sciences, the experimentation with human embryos is putting the human race at unnecessary risk since studies were already in progress to edit the same CCR5 gene in adults with Aids, without the risk of passing the modified genes on to the next generation.

The altering of somatic cells for the treatment of diseases is generally not regarded as controversial since it only affects the part of the body it belongs to and unlike stem or germ cells does not pass the modification on to future generations.

It is well-known fact that genes are interdependent - at least to some degree. An experiment with mice in disabling the CCR5 gene showed that the CCR5 gene (that was also disabled in the Chinese babies) is not just associated with HIV, but also plays a significant role in the inflammatory response and cognitive function.

In mice the disabling of CCR5 led to enhanced learning and memory capacity. This has led to widespread suspicion among scientists that He Jiankui may have had alternative reasons for modifying this particular gene.

Scientists are also perplexed by He Jiankui’s failure to publish his groundbreaking research in a credible journal.

Despite widespread scientific consensus for a moratorium until an international ethical framework has agreed on the circumstances and safety measures, the Russian molecular biologist, Denis Rebikov, declared in June 2019 similar plans to edit the DNA of human embryos to make them immune to HIV before the end of the year.

Rebrikov is leading a genome-editing laboratory at Russia’s largest fertility clinic, the Kulakov National Medical Research Center for Obstetrics, Gynaecology and Perinatology in Moscow and is a also researcher at the Pirogov Russian National Research Medical University in Moscow.

But perhaps there is some impudent thinking about how evolution can be shaped by science behind the Chinese embryo gene editing trial. While the natural mutation that disables CCR5 is relatively common in parts of Northern Europe, it is not found in China.

The distribution of a specific genetic trait in certain populations around the world illustrates how genetic engineering might be used to pick the most useful inventions discovered by evolution over the ages in different locations and bring them together in the children of the future. Such thinking could, in the future, lead to people who have only healthy genes and never suffer Alzheimer’s, heart disease, diabetes, or certain infections.

Although gene editing could eliminate genetic diseases in the future, it could also be the beginning of a slippery slope to cosmetic enhancements, designer babies and a new form of eugenics (improving the human race by encouraging reproduction by people with healthy genes and discouraging reproduction by people with unhealthy genes).

Most scientists support gene editing for the treatment and prevention of disease, but not for the enhancement of intelligence or physical looks that is not beneficial to society. It may even give rise to a new super human class and genetic class system giving those that can afford gene editing an unfair advantage.

Perhaps in future a gene-test will be required before you can marry and have children! But would that be very different from the current situation in the world?

Professor Louis C H Fourie is a futurist and technology strategist [email protected]


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