avatarSam Westreich, PhD


Could Gene Editing Create Smarter People?

All the other steps in the process that CRISPR doesn’t solve

We know this person is smart, because they have glasses… but did they get smart from gene editing? From CHEATING?? Photo by bruce mars on Unsplash

For as long as humans have known about genetics, that we each carry a unique blueprint in the DNA in our cells, we’ve wondered about making ourselves better. Could humans “edit their own code” and become taller, stronger, prettier, smarter?

It’s a question that has been around for decades, but discussion has been super-charged in recent years thanks to the discovery of CRISPR, an incredibly accurate pair of molecular scissors that can cut DNA at exact spots to make edits.

But we’ve got a ways to go. You likely don’t have to worry about a smarter, genetically engineered person taking your job. Medical therapies using CRISPR are being approved now

…but there’s still a big leap before it starts changing who we are.

Gene editing in 4 (not) easy steps

A very simple, straightforward blueprint for gene editing for a smarter human has several steps:

  1. Figure out which sequences in DNA you need to change.
  2. Create a custom-designed molecule that can make those specific changes.
  3. Put your custom molecule into all the cells you need to alter.
  4. Confirm the results, and that there aren’t any side effects.

How many of these steps do you think are currently possible?

If you’re pessimistic (but not too pessimistic) and guessed 1 out of 4, you’re correct! We can do step 2, but the others are still challenging. Get a small snack before continuing onward.

CRISPR is the commonly used term for a protein, called Cas9, that uses a short DNA sequence to match up to a specific spot in a cell’s DNA and make a cut there. (This is an oversimplification, but it’s also mostly correct.)

Our cells have enzymes that look for cut DNA and stitch it back together. But if we slip in an extra bit of DNA, or if a bit of the DNA is cut out and lost, it gets stitched back together a bit differently.

This approach works… decently well. CRISPR isn’t the first type of DNA-cutting scissors we’ve found, but it’s far more accurate than earlier versions. But there are still big challenges, for steps 1, 3, and 4 above.

Which areas do we even change?

The human genome is around 3.2 billion base pairs long. That’s 3.2 billion characters of A, C, T, and G. If printed out, it would fill about 3,000 textbooks.

If you take any two humans, they’re going to have pretty similar genomes, since the DNA says “how to build a human” in both. But there’s also a lot of variation, when we look closely; there are an average of 4–5 million bases, spread out across the whole genome, where any two people will differ. That’s only about a 0.1% difference in genetics from person to person, but that little fraction explains a lot of our variation.

And we don’t know what most of those 4–5 million mutations do. Some of those probably affect our intelligence, but each individual mutation likely has a very small, almost unnoticeable impact.

Humans do not just have an “intelligence gene” that is either “smart version” or “dumb version.” Instead, we’ve got millions of combinations, and that’s even before we take the environment (wealth, healthcare access, school quality) into account.

Frustratingly, most of the traits that we’d like to modify are just as complex. There are more than 12,000 different mutations that are linked to height.

Analogy time! Imagine that you flipped a coin 12,000 times, when you were born. Each “heads” flip made you slightly taller, while each “tails” flip made you slightly shorter. You’ll likely end up with around 6,000 “heads” flips, making you average height.

Now, with the power of GENETIC ENGINEERING, you can convert up to 5 “tails” into “heads” flips! Are you significantly taller?

Even though we can make some individual edits with CRISPR, there’s just too many spots to change, and each individual location has a very small impact.

And that’s assuming we can reach those spots at all.

If you’re reading this, it’s too late for you

CRISPR works on our DNA, but it needs to get to the DNA of our cells. You cannot simply put CRISPR in a cream or a pill and assume that it will make its way to every cell in our body.

The current CRISPR therapies work by taking cells out of our body, using CRISPR on them, checking to make sure the gene editing worked, and then injecting them back in. This works well for cells in our immune system that circulate freely in blood, or for stem cells in our bone marrow, but there’s no way for us to use this approach for our muscles or our entire skin.

If scientists wanted to edit a human’s genome, the best time (really, the only time) to do it is when they’re an embryo.

A fertilized egg is just a tiny little clump of cells, few enough to count on your fingers. Any edit made to the embryo would propagate up to every cell when that embryo becomes an adult.

That’s not a great answer if you’re trying to make yourself smarter without all that pesky studying, but it is the only option that would work today: have smarter children.

But there’s still risks. Which brings us to step 4.

If you come at the king (or genome), you best not miss

Remember how I said that CRISPR was an incredibly accurate pair of scissors, much more accurate than our old gene-cutting methods?

Incredibly accurate doesn’t mean perfect. And while it boasts a 99.9% or greater accuracy rate, that still means that CRISPR can accidentally make cuts at the wrong places. Cutting at the wrong place could just mean that the alteration doesn’t work. Or, in the worst cases, that cut could break a vital gene, leading to cell death or to cancer.

When we take the cells out a patient before treating them, we can monitor them to see if: A) the modification worked, and B) if the cells become cancerous. If they show markers of cancer, they don’t get injected back into the patient.

But modification in a live human is different. There’s no way to reverse the process. At least one person, Terry Horgan, has died, likely due to complications of the CRISPR delivery system setting off a fatal immune reaction.

Could you create a designer baby now?

All of this brings us back around to the original question: could you make someone smarter through meddling with their genes?

In short, no. We’d need to modify the embryo, so any editing would require in vitro fertilization (IVF), with edited embryos getting inserted into the mother (and hopefully leading to a successful full-term pregnancy). And we still aren’t sure which genes to modify to increase intelligence.

But there are two methods available right now to have a smarter, taller, offspring:

  1. Earn more money. Rich kids aren’t born innately smarter, but they do get more opportunities to develop their intelligence and skills, with better schooling and private tutors. (And you don’t need to worry about your genetics; even kids who are adopted into high-income families score higher on aptitude tests!)
  2. Use a sperm or egg donor. Hair color, eye color, and to a lesser degree, height, are all highly heritable from parents. You can’t alter the genes with CRISPR, but you can choose the genes by choosing donor parents who exhibit the traits you want.

For now, we don’t have the depth of genetic knowledge to know exactly what spots in the genome we’d need to modify to create smarter children. And we’d need to make those edits when the child is first conceived, to have them properly spread to all the child’s cells.

Instead, the best method at present is to improve the environment, the other half of the equation. No one is born with the ability to play chess at a grandmaster level, or to solve complex math equations, or to ace the SATs or other standardized tests.

Intelligence is learned. So for the near future, tutoring or a university class is probably a better choice than saving for gene therapy.

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