Cut-and-Paste Genes? Erm, Is that a Good Idea?

Contemplating the hopes and hazards of a crazy breakthrough called CRISPR.

By Crawford Kilian 15 Jan 2016 | TheTyee.ca

Crawford Kilian is a contributing editor of The Tyee.

In the 1930s, a scientific breakthrough slowly emerged into public discussion: it was now possible to split the atom, which in Greek means "unsplittable." In the process, enormous amounts of energy could be released -- especially in the form of a bomb, but also in the form of a nuclear reactor.

The last 70 years have been largely devoted to keeping such bombs from exploding and reactors from melting down. We have been lucky so far, apart from the residents of Hiroshima, Nagasaki, Chernobyl, and Fukushima, not to mention those millions of Americans downwind of the Nevada Test Site.

Now a comparable scientific breakthrough has emerged, and it poses a political and ethical problem at least as complex as nuclear fission and fusion. We can now "edit" ourselves and other plants and animals, just as this article has been edited -- but should we?

I won't tire you with the technical details. To cut to the proverbial chase, an American scientist named Jennifer Doudna looked at Japanese findings and realized bacteria are not just older, but smarter than we are. When attacked by viruses, bacteria had evolved a defensive response.

Their cut-and-paste technique is called "clustered regularly interspaced short palindromic repeats," CRISPR-Cas9 for short, and it enables bacteria to use enzymes that "cut" the DNA of invading viruses and stop them from replicating.

The same technique, now that we understand it, enables humans to rewrite themselves and other organisms -- an achievement likely superior to merely splitting atoms.

Unlike the 1930s, we're not staring at a world war, so the debate is out in the open. Scientists are both elated and alarmed at the prospect of cutting and pasting snips of genes that will change the organisms involved. And unlike the 1930s, CRISPR is not an issue to be decided by a handful of scientists and a president. We all need to help decide it.

Exterminating our greatest enemy

The positive aspects of genetic editing are really attractive. Humanity's greatest enemy is a mosquito, Aedes aegypti,* which carries yellow fever, dengue, chikungunya, and Zika virus. Tropical nations around the world struggle to suppress this mosquito.

CRISPR could transform A. aegypti by "gene driving" it into extinction, installing genes that will sterilize the mosquitoes that inherit them.

Visit Worldometers to see how many have died of malaria alone so far this year. Don't worry about the ecological impact of removing a mosquito species -- birds and bats won't starve, and many other species will thrive when the skeeters are gone.

With mosquitoes gone, what next? We could remove a host of plant and animal parasites and diseases, thereby increasing the food supply to support all the people no longer killed by mosquito-borne diseases.

And to support the people no longer doomed by genetic diseases. CRISPR is already curing mice with muscular dystrophy. Millions of children whose experience of life is nasty, brutish and short could escape the random curses their parents have put upon them. They could grow up as normal healthy people, without fear of passing the curse on to their own children.

We could do even more. By tinkering with our genes, we could extend our own life expectancies from decades to centuries.

Is this just more eugenics?

By now, alarms should be going off in your head. With a primitive grasp of genetics, our grandparents (and the Nazis) adopted eugenics -- essentially, applying dog breeding to humans -- to "improve" humanity by sterilizing or simply killing people considered inferior. This embarrassingly dumb idea inspired the Second World War and caused scores of millions of deaths. Could CRISPR be just a smarter way to implement the same dumb idea, with even worse results?

Very likely. But we flirted with nuclear warfare and managed to pull back from the brink, and we might push our luck again. Perhaps worse than the drawbacks of genetic editing are the hazards of success.

The first hazard is Malthusian: How do we feed all these extra hundreds of millions of healthy humans who now won't die before the age of five? What will it cost us to educate and employ them -- not just the money cost, but in species driven extinct as we expand into their habitats?

And what do we do with the 60th child of a 200-year-old woman with a strong maternal urge? CRISPR could put us all in the predicament of the House of Saud, finding places and incomes for countless little princes and princesses -- but we kings and queens, looking 25 at age 300, would have no interest in dying to make room for them.

Another hazard might be called Rumsfeld's Dilemma: When you don't know what you don't know, you can get into trouble. We might identify a gene responsible for a particular illness or disability, edit it out, and then discover that the gene also interacts with other genes in critically important ways. In effect, we'd be back to crude eugenics, but on a higher level.

Slaves to fashion

A third hazard: the evil of banality. Most human cultures like to idealize certain types of body, often by simple disfigurement or camouflage: elevator shoes make men look taller, and shoulder pads make them look brawnier. But fashions change, and sixpack abs would be sadly out of style if everyone else was going for an androgynous David Bowie body.

And a fourth: If you can cut and paste your own genes, do you risk violating someone else's copyright? When there's an app for eradicating hemophilia or progeria, should it be open source? Or should you pay whatever the developer charges?

In a recent op-ed, Margaret Somerville, founding director of the McGill Centre for Medicine, Ethics and Law, argued that "holding the human germline on trust [means] it must not be intentionally altered."

That would mean taking the same gambles our ancestors have always taken. We're the results of their luckier bets; natural selection has killed off untold millions of unlucky offspring (and many of their unlucky mothers as well). Perhaps we'd rather not think of the brutal process by which we've arrived, or the dumb luck that created us because one particular sperm cell got into our mother's ovum.

Dangerous sameness

Besides, we intentionally alter our own germline all the time, by mating with those our culture has taught us to find attractive. DNA studies have shown that most of humanity's genetic diversity is in Africa. The handful that emigrated into Asia and Europe and the Americas are comparatively inbred, and our racial characteristics are the result of the marriages of too many cousins.

CRISPR could inflict a dreary and dangerous genetic sameness on humans and other organisms, driven by cultural values like admiring big muscles or cute animals. The first virus to find its way into such homogeneous populations would slaughter them to the point of extinction.

So part of the price of perfect health and long life might be to accept a few genetic wild cards: new genes, whether natural or artificial, that might expose the organism to sudden death, or protect it. In effect, we would restore natural selection, despite its brutality, to our genetically edited ecosystem.

CRISPR is the genetic equivalent of a 1985-style word processor -- crude, clumsy, and limited. But those early word processors were far superior to the "natural" process of typed text. Now that we've seen what CRISPR can do, the race is on to develop far better editors, and in the process we'll have to learn far more about our own genetic makeup.

We will also learn much more about just how human we really are.

*Story corrected Jan. 17 at 11:20 a.m.  [Tyee]

Read more: Health

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