By Graham Duggan  

“Clustered Regularly Interspaced Short Palindromic Repeats” or “CRISPR” doesn’t sound very impressive, but don’t be fooled.

CRISPR (pronounced “crisper”) is a powerful tool that scientists can use to edit DNA and modify gene functions. Every cell has six billion letters of DNA code and just one wrong letter can leave someone with a debilitating illness. “Think about one misspelled word in a stack of one thousand bibles due to one wrong letter. That letter can put a boy in a wheelchair,” says molecular biologist Eric Olsen.

By mapping the human genome, we now know the DNA errors that are at the root of nearly 7,000 diseases — and we can use CRISPR to fix them. The technology acts like a spell-checker, locating a specific DNA sequence, removing and replacing it.

While this technology has the power to heal, we learn in the Nature of Things documentary The Genetic Revolution, it’s changing our world in all kinds of unexpected ways.

The dawn of designer babies

CRISPR has the potential to turn human reproduction on its head.

Fertility specialist John Zhang is at the cusp of “human engineering” and has successfully used the DNA of three adults to create a three-parent baby. Since it’s illegal to implant an altered human embryo into a patient in the U.S., Zhang had to travel to Mexico to perform the treatment and says, “from this point on we know human reproductive medicine is going to change forever.”

While this method has the potential to produce a child who might otherwise suffer from a hereditary disease carried by one parent, applications could go beyond that, says Marcy Darnovsky, executive director for the Centre of Genetics and Society. 

But the use of CRISPR can go further. “You get the parents who say, “Well, since we’ve invested this much money in making sure our child doesn’t have a higher risk of breast cancer, let’s also choose, whatever, hair colour, skin colour, eye colour,” says Darnovsky. And Zhang agrees, “I think the public will utilize the designer baby technology.” 

The United Kingdom recently became the first country in the world to permit the use of “three-person IVF” to prevent incurable genetic diseases, so there’s no doubt — more three-parent babies, and possibly designed babies, are on the way.

Growing new human organs … in pigs

Pablo Ross, a biologist from the University of California is conducting some cutting-edge research that he hopes has the potential to save millions of lives. Ross is placing human cells into pig and sheep embryos and hopes to combine the DNA of two species to create an almost endless supply of replacement organs for humans.

It sounds like something right out of a science fiction novel — and it is. In Oryx and Crake, Canadian author Margaret Atwood imagined a world where pigs were infused with human DNA, raised for their organs and then discarded. It didn’t end well, as the “pigoons” became dangerous predators who devoured their human creators.

For now, in this study, the pig-human embryos are terminated at 28 days — well before birth, but Ross is hopeful for the future. “Pigs that nowadays are being grown to provide meat and bacon for breakfast... could also provide life-saving organs.”

MORE:
Human gene editing could change the world — what are the laws governing it in Canada?

Genetically engineering entire populations

Altering the genetic code of organisms comes with a lot of unknowns, but that hasn’t stopped some scientists, like Kevin Esvelt, who leads the ‘Sculpting Evolution’ lab at MIT, from wanting to try it out on a large scale.

He is working on a technique called a “gene drive”, a way of editing an animal’s genetic code and have changes passed down to their offspring, eventually creating a new genetically modified population. “No one had imagined that we would be able to edit entire wild species. We could get rid of all sorts of other incredible health problems,” claims Esvelt.

His work has focused on eliminating Lyme disease, a bacterial infection carried by white-footed mice and transferred to humans through tick bites. A small percentage of mice are naturally immune to Lyme disease, and “we can, using CRISPR, insert that [immunity] DNA into the reproductive cells of mice, so their offspring will inherit that immunity,” he says. From there, Esvelt plans to release the immune mice back into the wild, where he hopes they will reproduce and pass on their immunity, eliminating Lyme disease in the entire population.

Studies are also underway to reduce the rate of malaria in mosquitoes, a disease that kills nearly half a million people each year.

While CRISPR could bring us huge benefits, the stakes are high. Nobody wants a “Franken-mouse.”

Esvelt, the designer of the gene drive, is wary however, and working on an “undo” button in case it goes wrong in the wild. Until then, he urges scientists not to use his own creation, “some boxes should be left closed. More than technological power, it is wisdom we need.”

Watch The Genetic Revolution on The Nature of Things.

 

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