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Brought to you in partnership with… The Dyad Institute. You. More.
With the popularity of TV shows like Orphan Black, the idea of human cloning is hot on
the brains of everyone and their sister… and their sister, and their other sister,
and their other other sister. And their brother.
Thanks to modern advancements in genetics and synthetic biology, we might have the power
to manipulate the human genome in ways that could let us engineer ourselves or our offspring
to be free of disease, even to have customized traits.
But could actual human clones really exist? Well…
Hey, Dyad sent me. They want me to co-host this episode with you or something.
Um, okay! Gotta do what the sponsor says, I guess! You look really, um, nevermind.
So, yeah. Clones could exist. They already do.
We call them identical twins.
Identical twins are the result of a single fertilization,one sperm and one egg, that
splits into two embryos. So they start out with the same genetic material…
but even “identical” twins aren’t, like, totally identical.
In early development, they get hundreds, maybe thousands of random mutations in every cell
of their body that their twin won’t share.
And no matter what the movies want you to think, identical twins have different personalities
and don’t even always look completely alike. Even two genes that are the same, letter-for-letter,
can be act differently thanks signals on the DNA molecule itself. It’s epigenetics, and
it’s how genetically identical organisms can turn out very differently.
This continues for their whole lives, genetic changes adding up in different cells of the
body. We’re not even genetically identical to ourselves, man.
Speaking of clones, I was just shopping at my local organic farm-to-table market and
I ran into some clones there, like this avocado, this apple, an orange.
Even this banana! Actually pretty much all of the fruits and veggies we buy are genetically
identical clones.
Scientists have also been working to make cloned animals, by taking the DNA out of an
unfertilized egg and replacing it with the DNA of an adult animal, the whole nucleus.
Now, there’s talk of bringing back some extinct animals, like big wooly mammoths!
Researchers have already done this on several living animals, including Dolly the sheep,
dogs, even a cute little kitty named CC, for Carbon Copy. Aww. I would have named the cat
Felix, myself, but that's just my opinion. Because of mutations and epigenetics, just
like twins, those cloned animals are slightly different than their genetic parents, or siblings,
or however that works out. I mean they might be clones, but they’re
individuals, right? How much difference does it take to be yourself?
Good question. Thanks!
You know, it goes beyond cloning. This stuff might be able to save lives.
Now that the human genome has been sequenced, we’ve identified genetic variants that increase
the risk of certain diseases, like breast cancer.
We’ve also zeroed in on genes that influence more superficial things, like eye color.
Change those DNA sequences in a sperm or an egg, and you could make “designer babies”
with customized genes, they’ll even pass those changes on to their offspring.
We currently have the technology to do just that, with gene editing tools like CRISPRs,
where a short piece of RNA guides a sort of molecular pair of scissors to snip a particular
DNA sequence, letting us to change any sequence in any organism
at will. They’re easy to make, and it’s been done
lots of times in other animals.
And we don’t even have to modify the DNA in the nucleus. Some rare diseases are caused
by mutations in mitochondrial DNA. Fertilized eggs can have their mitochondria swapped out
for mitochondria from a donor that doesn’t carry that mutation, and then they’re implanted
in the mother. This so-called “three parent in vitro fertilization”
was recently made legal in the United Kingdom, but it's still outlawed in most of the world.
Um, excuse me. Who do those genomes belong to? I’m… um, asking for a friend.
Well as of now in the United States, naturally occurring DNA can't be patented. Like that
gene variant for the breast cancer gene BRCA1, that's already found in nature, nobody can
own that. But synthetic genes, DNA that we custom make, which we can also do, well those
belong to whoever makes them.
They should put, like, barcodes on those or something so they know who that DNA belongs
to.
They could probably do that, actually. Synthesizing DNA is really cheap and easy.
In fact, we can already do most of this stuff in humans, cloning, designer genetics… at
least in theory. But while we’re willing to test these technologies
on plants, sheep, rats, dogs, they’re off limits in people, we don’t completely know
how they work. It’s sort of a futuristic chicken and the
egg problem, in order to to know if these technologies are truly safe for people, if
their benefits outweigh their risks, we’ll need to do some amount of human testing, or
at least testing on human cells, but until we know how safe they really are, most people
have declared that it’s too risky or even unethical to do that testing.
What do you think? Do technologies like cloning and human genome modification represent a
bright new future, or a dark and scary one? What should we be worried about, or is it
all good in the name of progress? Let me, or us know in the comments, or on
Twitter. Are you guys on Twitter?
What's up everybody?! I'm here for the shooting! What? I had to get cappuccino.
Stay curious!