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  • We've been able to clone human embryos

  • for about seven years.

  • But as far as we know,

  • no one's actually cloned a whole person.

  • Turns out, ethics aren't the only thing

  • holding scientists back.

  • Cloning isn't the sci-fi marvel we think it is.

  • It can be dangerous, often ineffective,

  • and, most of all,

  • we just haven't thought of a good enough reason to do it.

  • So, here's why you'll probably never

  • have to fight your evil clone.

  • This is Dolly.

  • Just kidding, that's a regular sheep.

  • This is Dolly,

  • the first mammal cloned successfully from an adult cell.

  • She was born in 1996 after scientists figured out

  • how to remove the DNA

  • from the egg cell of a Scottish Blackface sheep

  • and basically replace it with the DNA

  • of a mammary cell from a Finn Dorset sheep.

  • They gave it a little electric shock

  • to fuse the cell and get it replicating,

  • placed the cells in the uterus of another sheep,

  • and boom, clone.

  • This method, called reproductive cloning,

  • could theoretically be used on humans.

  • But this is a best-case scenario.

  • It took 277 tries

  • for the scientists to get one Dolly.

  • Nowadays, cloning mammals generally has a success rate

  • of about 10% to 20%.

  • Better than one in 277,

  • but still a majorly inefficient process.

  • Jose Cibelli: Technically, it's not difficult

  • to produce a clone embryo,

  • but human cloning has other hurdles

  • that need to be considered.

  • Narrator: To even research human cloning,

  • scientists would need to ethically collect

  • a large amount of donated eggs

  • and find enough surrogates to carry them.

  • But even if they made it through that logistical nightmare,

  • the biggest issue is this:

  • Cibelli: They're gonna hurt the baby,

  • or they're gonna hurt

  • the person carrying the cloned fetus.

  • Narrator: Across the board,

  • scientists have found that some embryos

  • expire before they're implanted.

  • Others result in miscarriages.

  • And those that make it to term

  • often die soon after birth

  • or end up with severe abnormalities.

  • Simply, these are risks that are easier to take

  • when it comes to experimenting with sheep than with people.

  • But arguably the biggest reason

  • we haven't cloned a human being?

  • There's not a good enough reason to.

  • In pop culture, cloning is used

  • to bring people back from the dead.

  • But that's not how it works.

  • Cloning someone would only create a twin, not a replica,

  • since identical twins have the same genetics,

  • but not necessarily personalities.

  • And a "Never Let Me Go" scenario,

  • where organs are harvested from clones to save the rich,

  • is not only unethical, but unnecessary.

  • Why clone an entire person

  • when you can just make the part you need?

  • Something, theoretically, therapeutic cloning can solve.

  • Therapeutic cloning is almost identical to reproductive,

  • except the cloned embryo is never implanted in a uterus.

  • Instead, the embryo is cloned

  • for the sole purpose of extracting stem cells.

  • Stem cells have the incredible ability

  • to turn into any other cell in the human body,

  • which means they're great

  • for developing new treatments for disease

  • and have the potential to repair

  • or regenerate tissues and organs.

  • But, no surprise,

  • there are a lot of downsides with therapeutic cloning.

  • The thing about stem cells

  • is that they're a pretty limited resource.

  • The most substantial source for embryonic stem cells?

  • Three- to five-day-old embryos,

  • cloned or otherwise.

  • And when someone else's stem cells

  • are transplanted into a patient,

  • the body will sometimes fight them off like a disease.

  • Some researchers believe that cloned stem cells,

  • since they share the patient's DNA,

  • would be less likely to be rejected.

  • But this use case is still in the research stage.

  • And, finally, therapeutic cloning

  • is an individualized treatment

  • in a world where drug companies

  • are more interested in standardized ones.

  • And there are easier ways

  • to create multipurpose cells nowadays,

  • like the method for creating induced pluripotent stem cells.

  • They're basically adult cells

  • that have been reprogrammed to be a different type of cell.

  • Cibelli: The problem with therapeutic cloning,

  • of course, is that you need a lab personnel

  • that is qualified to do it, specific equipment to do it.

  • Whereas the other technique,

  • you can just buy a kit and one person can do it

  • in a lab that has some expertise in tissue culture.

  • Narrator: Cloned cells still have an advantage

  • when it comes to healthier mitochondria

  • and the ability to grow into entire animals,

  • whereas iPSCs often peter out.

  • But since iPSCs safely and reliably do most everything

  • but create entire living animals,

  • why fund the harder, ethically ambiguous thing?

  • So, cloning might actually have a bigger place in movies

  • than it does in real life,

  • because the money just isn't there.

  • And just because we can do something

  • doesn't mean we need to.

  • Ian: Your scientists were so preoccupied

  • with whether or not they could,

  • they didn't stop to think if they should.

  • Abby Tang: So, in the research for this video,

  • I did come across one very interesting tidbit,

  • and that is the announcement of cloned human baby Eve,

  • who was born on December 26, 2002.

  • And the source of this announcement

  • is a company called Clonaid,

  • which was formed in 1997 by the Raelian cult.

  • And they're a cult that believes

  • that humans were cloned from aliens

  • and the only way for us to reach immortality

  • is to clone ourselves.

  • It's been 18 years,

  • and we haven't gotten any proof that baby Eve exists

  • or has ever existed,

  • but the company is still alive and well.

  • So if any proof does come through, we will update you.

  • Subscribe below so you don't miss it.

We've been able to clone human embryos

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B2 H-INT US cloning cloned clone stem therapeutic sheep

Why We Still Haven't Cloned Humans

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    river   posted on 2020/10/13
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