Tag Archives: Technology

Gene drives and gingivitis bacteria

One piece of sci-fi technology that doesn’t get much talk these days is gene drives. When I was an up and coming biology student, these were the subject of every seminar, the case study of every class, and they were going to eliminate malaria worldwide.

Now though, you hardly hear a peep about them. And I don’t think, like some of my peers, that this is because anti-technology forces have cowed scientists and policy-makers into silence. I don’t see any evidence that gene drives are quietly succeeding in every test, or that they are being held back by Greenpeace or other anti-GMO groups.

I just think gene drives haven’t lived up to the hype.

Let me step back a bit: what *is* a gene drive? A gene drive is a way to manipulate the genes of an entire species. If you modify the genes of a single organism, when it reproduces only at most 50% of its progeny will have whatever modification you give it. Unless your modification confers a lot of evolutionary fitness to the organism, there is no way to make every one of the organism’s descendants have your modification.

But a gene drive can do just that. In fact, a gene drive can confer an evolutionary disadvantage to an organism, and you can still guarantee all of the organism’s decedents will have that gene. The biggest use-case for gene drives is mosquitoes. You can give mosquitoes a gene that prevents them from sucking human blood, but since this confers an evolutionary disadvantage, your gene won’t last many generations before evolution weeds it out.

But if you put your gene in a gene drive, you can in theory release a population of mosquitoes carrying this gene and ensure all of their decedents have the gene and thus won’t attack humans. In a few generations, a significant fraction of all mosquitoes will have this gene, thus preventing mosquito bites as well as a whole host of diseases mosquitoes bring.

Now this is a lot of genetic “playing God,” and I’m sure Greenpeace isn’t happy about it. But environmentalist backlash has never managed to stamp out 100% of genetic technology. CRISPR therapies and organisms are on the rise, GMO crops are still planted worldwide, environmentalists may hold back progress but they cannot stop it.

But talk about gene drives *has* slowed considerably and I think it’s because they just don’t work as advertised.

See, to be effective a gene drive requires an evolutionary contradiction: it must reduce an organism fitness but still be passed on to the progeny. Mosquitoes don’t just bite humans for fun, we are some of the most common large mammals in the world, and our blood is rich in nutrients. For mosquitoes, biting us is a necessity for life. So if you create a gene drive that knocks out this necessity, you are making the mosquitoes who carry your gene drive less evolutionarily fit.

And gene drives are not perfect. The gene they carry can mutate, and even if redundancy is built in, that only means more mutations will be necessary to overcome the gene drive. You can make it more and more improbable that mutations will occur, but you cannot prevent them forever. So when you introduce a gene drive, hoping that all the progeny will carry this gene that prevents mosquitoes biting humans, eventually one lucky mosquito will be born that is resistant to the gene drive’s effects. It will have an evolutionary advantage because it *will* bite humans, and so like antibiotic resistant bacteria, it will grow and multiply as the mosquitoes who still carry the gene drive are outcompeted and die off.

Antibiotics did not rid the world of bacteria, and gene drives cannot rid the world of mosquitoes. Evolution is not so easily overcome.

I tell this story in part to tell you another story. Social media was abuzz recently thanks to a guerilla marketing campaign for a bacteria that is supposed to cure tooth decay. The science can be read about here, but I was first alerted to this campaign by stories of an influencer who would supposedly receive the bacteria herself and then pledged to pass it on to others by kissing them. Bacteria can indeed be passed by kissing, by the way.

But like gene drives, this bacteria doesn’t seem to be workable in the context of evolution. Tooth decay happens because certain bacteria colonize our mouth and produce acidic byproducts which break down our enamel. Like mosquitoes, they do not do this just for fun. The bacteria do this because it is the most efficient way to get rid of their waste.

The genetically modified bacteria was supposed to not produce any acidic byproducts, and so if you colonized someone’s mouth with this good bacteria instead of the bad bacteria, their enamel would never be broken down by the acid. But this good bacteria cannot just live in harmony and contentment, life is a war for resources and this good bacteria will be fighting with one hand tied behind its back.

Any time you come into contact with the bad bacteria, it will likely outcompete the good bacteria because it’s more efficient to just dispose of your waste haphazardly than it is to wrap it in a nice, non-acidic bundle first. Very quickly the good bacteria will die off and once again be replaced by bad bacteria.

So I’m quite certain this little marketing campaign will quietly die once its shown the bacteria doesn’t really do anything. And since I’ve read that there aren’t even any peer reviewed studies backing up this work, I’m even more certain of its swift demise.

Biology has brought us wonders, and we have indeed removed certain disease scourges from our world. Smallpox, rinderpest, and hopefully polio very soon, it is possible to remove pests from our world. But it takes a lot more work than simply releasing some mosquitoes or kissing someone with the right bacteria. And that’s because evolution is working against you every step of the way.

If the weavers get replaced by machines, who will buy the clothes?

I’ve seen way too many articles about AI casting doom and gloom that it will “replace millions of jobs” and that this will lead to societal destruction as the now job-less replacees have no more money to spend.  The common refrain is “when AIs replace the workers, who will buy the products?”

This is just another fundamental misunderstanding of AI and technology.  AI is a multiplier of human effort, and what once took 10 men now takes 1.  That doesn’t mean that 9 men will be homeless on the street because their jobs are “replaced.”  The gains reaped from productivity are reinvested back into the economy and new jobs are created.

When the loom replaced hand-spinning weavers, those weavers were replaced.  But they could eventually find new jobs in the factories that produced looms, and in other factories that were being developed.  When computers replaced human calculators, those calculators could now find jobs programming and producing computers.

For centuries now, millenia even, technology has multiplied human effort.  It used to take dozens of people to move a single rock, until several thousand years ago someone had the bright idea of using ropes, pullies, and wheels.  Then suddenly rocks could be moved easily.  But that just in turn meant the demand for moving rocks shot up to meet this newer, cheaper equilibrium, and great wonders like the Pyramids and Stonehenge were suddenly built.

The same will be true of AI.  AI will produce as many new jobs as it creates.  There will be people to produce the AI, people to train the AI, people to ensure the AI has guardrails and doesn’t do something that gets the company trending on Twitter.  And there will be ever more people to use the AI because demand is not stable and demand for products will rise to meet the increase in supply generated by the AI.  People will want more and more stuff and that will lead to more and more people using AI to produce it.

This is something that people get hung up on, they think that demand is stable.  So when something that multiplies human effort gets created, they assume that since the same amount of products can be produced with less effort, that everyone will get fired.  Except that demand is not stable, people have infinite wants and finite amounts of money. 

Technological progress creates higher paying jobs, subsistence farmers become factory workers, factory workers become skilled workers, skilled workers enter the knowledge economy of R&D.  These new higher paying jobs create people who want more stuff because they always want more stuff, and now have the money to pay for it.  This in turn increases demand, leading to more people being employed in the industry even though jobs are being “replaced” by machines.

To bring it all back to weavers, more people are working in the textile industry now than at any point in human history, even though we replaced weavers with looms long ago.

AI will certainly upend some jobs.  Some people will be unable or unwilling to find new jobs, and governments should work to support them with unemployment insurance and retraining programs.  But it will create so many new jobs as well.  People aren’t satisfied with how many video games they can purchase right now, how much they can go out to restaurants, how much housing they can purchase, etc.  People always want more, and as they move into higher paying jobs which use AI they will demand more.  That in turn will create demand for the jobs producing those things or training the AIs that produce those things. 

It has all happened before and it will happen again.  Every generation thinks that theirs is the most important time in the universe, that their problems are unique and that nothing will ever be the same.  Less than three years ago we had people thinking that “nothing will ever be the same” due to COVID, and yet in just 3 short years we’ve seen life mostly go back to normal.  A few changes on the margins, a little more work from home and a little more consciousness about staying home when sick, but life continued despite the once-a-century upheaval.

Life will also continue after AI.  AI will one day be studied alongside the plow, the loom, and the computer.  A labor-saving device that is an integral part of the economy, but didn’t lead to its downfall.