Posted by on February 25, 2018 2:57 pm
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Source: CRISPR will save lives – and technology can't come soon enough

Humans have been tinkering with genes for as long we know. It’s why we have edible bananas instead of bulbous things with hard seeds, or corn that looks like corn and not grass. Well before the discovery of the gene, we’ve been breeding them in and out of plants and animals with absolutely no way of knowing what our introduced modifications do, where they end up in the genome, or how they might affect the environment.

Here’s the paradox: modern gene technology is far less genetically invasive – and much better understood – than the time-worn practice of selective breeding, and yet so many of us live in fear of genetically modified organisms. Instead of adding, removing, or reshuffling thousands of unknown genes in order to breed traits in or out of organisms, we’re now able to act on just one well-characterised gene with precision.

We didn’t need high-powered biotech to create dachshunds or bulldogs from ancestral wolves. The same breeding techniques that gave us virtually all of the food we now eat also has given our companions a predisposition to spinal problems and breathing difficulties.

Sinister. But short of us reverting to cave-dwellers, there really is no way out of it. Even kale, the staple crop of the inner city, started off as a weed.

Selective breeding is the cornerstone of agriculture, and civilisation might never have emerged without it. But compared with molecular methods, it’s like driving in a screw with a sledgehammer.

Enter CRISPR. This is a promising new gene editing technology that promises greater affordability and precision than ever before. It works by cutting through the DNA at a specific point, like a pair of molecular scissors. By taking advantage of the cell’s own DNA repair mechanisms, we’re able to insert, edit, or delete genes, in some cases down to a single unit of genetic code.

The potential applications of CRISPR are enormous. It’s the closest we’ve ever come to a cure for cancer. We’ve already been able to cure HIV infection in animal models, and even in human cell cultures, by removing the viral genes that insert themselves into our DNA. Incurable genetic diseases, like Duchenne’s muscular dystrophy, could soon be a thing of the past. CRISPR has already been used to cure the disease in rats.

But some are not so convinced. Couldn’t this technology be used to create a dystopia where only the rich can afford genetic enhancements to make themselves better, faster, stronger?

The short and long answer is no. There are limits to gene technology. When progressives shun gene technology for fear of creating a race of artificial super-humans, they unknowingly surrender to dangerous and discredited ideas that reek of the same eugenics they want to combat.

There are no “superior” genes, and therefore no way to create genetically superior humans. There are only genes that confer a selective advantage in a specific environment. Because I have darker skin, I’m less likely to develop melanoma. I’ve never even experienced sunburn. My skin colour is advantageous in sunny Australia, but not so useful in Scandinavia, where I could end up with a vitamin D deficiency.

Only a few traits are decisively linked to a single gene, like some types of red-green colourblindness (which, by the way, makes you better at seeing camouflage). But there’s no single genetic switch for abstract traits like intelligence or sexuality.

Even though there are a few dozen genes that are thought to contribute to intelligence, none of them do so in any way significant enough for us modify. At best they contribute a slightly increased probability, not a guarantee, that someone will be smarter. Some of them are also associated with schizophrenia, Alzheimer’s, and even obesity. Can you really call these genes superior? You’d be far better off getting a library membership.

Our genome is a biological balancing act, reliant on what is more advantageous to our survival. Even disease genes can be advantageous in certain environments. People with one copy of the sickle-cell disease gene, which causes a red blood cell deformity, are protected against malaria. This is largely why natural selection has not already created a race of super-humans. We are all born equal parts gifted and cursed.

Precisely because of this, CRISPR doesn’t even require us to insert any new genes at all for it to deliver. The chemical responsible for the browning of avocadoes is useful for the plant in the wild, but not so much when grown for agriculture. The same goes for allergens in nuts. With CRISPR, we can turn those genes off with minimal disruption to the genome.

It’s worth pointing out these gene deactivations crop up in nature all the time without any human intervention. A single genetic event was all it took to turn bitter almonds, containing lethal levels of cyanide, into the sweet variety we all love and enjoy.

The future of gene technology is a matter of public importance. CRISPR could revolutionise medicine and agriculture, but we still have a mountain to climb before we can put it to use. While we don’t think that there is a straightforward correspondence between genes and things like musical ability, we do think that such technology will have the potential to change things like hair, eye, and even skin colour. Where we should draw the line is up for debate. But one thing is clear: we need gene technology on our side.

It will be some time before we can say for certain that the technology is without side-effects, and even then there are challenges in getting the CRISPR mechanism into living cells. We’re getting there. But for some, the technology could not come soon enough. CRISPR will save lives.

Fahad Ali is a geneticist and member of the Sydney Nano Institute and the Sydney Institute of Agriculture. He works in developing novel delivery methods for the CRISPR mechanism in plant cells.

Published at Sun, 25 Feb 2018 13:01:00 +0000

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