基因（Gene editing: should you be worried? | The Economist）

字幕列表影片播放

The gene-editing revolution has arrived...
...promising cures for terminal disease
For the past five years...
...we've made more progress than in the previous 50
And new approaches to fighting climate change
We have the opportunity to fundamentally...
...change our relationship with nature
But new genetic technologies bring with them...
...new ethical and practical risks
Say no to GMO
Some of it could be terrifyingly threatening like biowarfare
What is our responsibility as scientists and doctors?
That's really starting to bring out ideas around...
...who belongs and who doesn't belong
So, how should the promise of genetic technologies...
...be balanced against the potential dangers?
And who decides what risks are worth taking?
This is Professor James Dale...
...a man on a mission...
...to save the world's most popular banana from extinction
I reckon these Williams are the ones that were most spectacular...
...weren't they?
That's incredible
There are thousands of types of banana in the world...
...but all the fruit being grown and processed here...
...and almost every banana exported around the world...
...is one single variety, the Cavendish
It yields very well
It's got quite a tough skin so it travels well...
...but also it's got a really acceptable taste and texture
The problem is, the Cavendish is under threat...
...a disease known as Tropical Race 4 or TR4...
...has spread across the world, killing Cavendish bananas
TR4, one of the deadliest plant diseases out there
They call it the cancer of the bananas
You start to get that sort of motley colouration there...
...it gets worse there
And now it's reached James's plantation
And what we're looking for is the brown...
...which is what we call necrosis
And then you see, bingo, that was one that had the yellow leaves...
...just incredible necrosis
There is no cure for this disease
It's feared that in time, it could wipe out the Cavendish completely...
...or stop it being such an economically valuable crop
It is a really serious problem
There's no obvious replacement...
...for Cavendish bananas for the export market
But James has a solution
He has spent ten years engineering a genetically modified banana...
...which can withstand TR4
There's a big problem though
Say no to GMO
Because James's bananas are genetically modified...
...lots of consumers won't go anywhere near them
It is unbelievably frustrating
GM still has a lot of perceived negativity in the world
Europe, for instance, is one of those areas that they import...
...huge amounts of bananas but getting a GM crop...
...through the regulatory process in Europe is virtually impossible
He believes this public resistance...
...could block the development of beneficial new crops
I think it's a real problem, we're moving into a period of real flux...
...a real unknown period with climate change and we're going to need...
...to develop crops that have very high tolerance to drought
I'm not sure that we have all of the tools at our fingertips...
...without the use of GM and gene editing
So, I think there is a real ethical dilemma in the world now...
...of rejecting technologies that may become incredibly important...
...over the next decade or two
Some believe GM technology can be used to do lots of good
So, is it right to put barriers in the way...
...because others oppose the technology on principle?
In an EU-wide poll, 70% said they felt GM foods were unnatural...
...but that's a very vague term
The things that people actually grow in gardens...
...and in fields are really not particularly natural
Many of them have genomes that have been extensively changed...
...over the course of human history
If you look at what a modern ear of maize looks like...
...compared to its ancestral form, you'll see something very different
Yet there is still a fear that these technologies could go astray...
...and expose people to risks they have not agreed to
This is Islamorada, a tropical paradise...
...that's on the front line of the debate about genetic engineering
Here, genetically modified mosquitoes are being released....
...in the United States for the first time
It's part of an experiment to try to reduce...
...the spread of Zika and dengue fever
But some of the locals have been very vocal about their opposition...
...to this kind of intervention into the natural world
Our economy here is tourist-based and a lot of tourists are laypeople...
...and if they come down here and they hear that we're turning loose...
...some kind of weird critter, I think that there could be...
...some impact on the economy
As a result, the mosquitoes have to be released...
...in top secret locations, away from protesters and vandals
We just add regular tap water, the eggs hatch in about 24 hours
There's already food in there...
...and you can see these little holes on both sides...
...that's where the adult males are going to come out of
The authorities hope this will solve the problem...
...posed by Aedes aegypti, a mosquito which can carry Zika...
...and dengue, and in some places, has become resistant to pesticides
Aedes aegypti control is very expensive
What we find is that, it takes up over 10% of our entire budget...
...to control a very small population of our mosquitoes
Up till now, mosquito control here...
...has involved going door to door clearing standing water
British company Oxitec might put an end to that...
...with a genetic approach that has female mosquitoes in its sights
Only the females bite and carry disease...
...and Oxitec is getting to them through the males
It altered the genes of some male mosquitoes...
...so that when they mate with females...
...only their male offspring would survive...
...meaning the number of females should crash within a few generations
It's essentially birth control for mosquitoes
It's a biological solution
It's targeted against one species...
...and it has no effect against bees, butterflies or other pollinators
The project is a field trial, which has been approved...
...by America's Environmental Protection Agency, the EPA
But the way the technology is regulated has provoked concerns
The protocols for evaluating genetically modified organisms...
...are way short on a lot of things
Natalie Koffler is a Harvard-based bioethicist who has attended...
...many of the town-hall debates about this programme
What I'm really concerned about is, is really how it's being decided...
...upon and developed, not the technology itself
She says the regulation of this technology isn't transparent enough...
...and doesn't require proper engagement with affected communities
It's just blowing our regulatory systems apart
One of the biggest challenges is the real need for community consent...
...when we're talking about releasing genetically modified organisms...
...into people's, literally, like backyards
We don't have a space that empowers community members...
...in this process or gives them any real sort of agency...
...that, to me, is a really, really big concern
Failing to engage communities properly not only risks intervening...
...in their lives without consent, it also raises another ethical concern
The risk of turning people against the technology, meaning that they...
...and others miss out on beneficial interventions
By not engaging communities, we're setting up GMO storm 3.0...
...where, you know, we already have so much distrust in that space...
...this could just, you know, create entirely new concerns
The emergence of new types of gene editing...
...is raising the stakes in this debate
Gene editing is getting cheaper and easier...
...making the technology more widely available
One of the biggest recent advances has been the development...
...of a technique known as CRISPR...
...which in 2020 won a Nobel prize for its inventors...
...Emmanuelle Charpentier and Jennifer Doudna
Human beings now have the ability to rewrite the code of life
CRISPR makes precise edits in DNA by using a special protein...
...which can be programmed with a molecule called RNA
So that when it finds a specific gene sequence...
...it makes a cut at that precise point in the DNA
The technique's combination of precision and ease of use...
...opens up the prospects of tackling genetic diseases...
...more effectively than ever before
You cranked her up, jumped into the front seat...
...and off you went with a family
I think of CRISPR as being kind of like the Model T Ford
There were cars before the Model T...
...but they were really expensive and they broke down all the time
Once the Model T came out, everybody could have a car...
...and so with CRISPR, it's just faster, cheaper, easier, better
Mighty smooth riding now
This ability to edit specific genes...
...could change medicine dramatically—and soon
There are 200m people on our planet, our fellow human beings...
...who suffer from genetic diseases that are CRISPR-able in principle
One of the most recent advances...
...is the ability to treat sickle cell disease...
...a blood disorder which is caused by a mutation in a single gene
This new technology is already here and already changing lives
This new technology is already here and already changing lives
Josh Lehrer runs Graphite Bio...
...a company researching CRISPR-based cures for the disease
He was inspired by his time as a junior doctor...
...when sickle cell treatment was basic
I was in medical school taking care of my first patient...
...with sickle cell disease and we had really nothing to offer...
...besides morphine and blood transfusions which were essentially...
...the same ways that this disease was treated in the 1950s
Nothing had really changed
What we're hoping to find here is ways...
...to actually kind of keep improving the efficiency
Josh's company is working on what he calls...
...next-generation gene-editing treatments
If we had an approach that could go beyond cutting...
...and essentially find and replace, correct that defect and restore...
...the normal haemoglobin protein, that should be a definitive cure
While most would be in favour of using gene editing...
...to cure a disease like sickle cell...
...it gets more complicated when the technology is used to fix diseases...
...and conditions, which may be less debilitating
I think what bothers people a lot about gene editing...
...isn't the idea of editing away terrible diseases
It's the idea of editing traits that aren't diseases at all...
...like eye colour or skin colour
I think these are going to raise some really difficult questions
At this lab in Moscow, scientists are engaged...
...in one of the most controversial applications of CRISPR
They're using gene editing to try to eliminate hereditary deafness
Denis Rebrikov, who leads the research...
...says he has three deaf couples lined up for treatment...
...and that this would be the only way...
...they could have a child who can hear
While Denis does not yet have approval from the Russian regulators...
...to implant edited embryos into patients...
...he hopes it will only be a matter of time
And for many deaf people, and beyond...
...this is a deeply troubling prospect
Teresa Blankmeyer Burke is a bioethicist...
...who teaches at Gallaudet University, a college for the deaf
So guess what, deaf people are not the first people to give us information
Whenever we have technology that can change the world...
...we need to be very thoughtful about how we use it
She worries using CRISPR to cure deafness could damage efforts...
...to improve understanding and integration of deaf people
I think we are experiencing a deaf renaissance...
...that this kind of experience, this kind of community...
...needs to continue, but we can't continue...
...if we have the threat of dissolving us as a people
Some fear editing genes related to conditions like deafness...
...could pave the way towards building so-called designer humans
The gene-editing conversation is important...
...because it's really starting to bring out ideas around...
...who belongs and who doesn't belong
And I think those are really important social questions...
...that we need to reckon with
Many rich countries already offer screening to pregnant women...
...for disorders like Down's syndrome...
...and some fear the elimination of conditions like this
...would simply be a logical next step and set a worrying precedent
It's an evolution of pre-implantation genomics
We have selective abortion
We're already choosing potential for genetic disorders, etc
It's just one next step then just maybe being able to...
...tailor those genomes for certain traits
Editing embryos is especially controversial...
...because it can cause genetic changes to be passed down...
...through the generations via what is known as germline editing
So germline editing affects potentially at least your children...
...grandchildren, great grandchildren...
...and potentially until the end of the species
The doctor who sparked global outrage by claiming...
...to produce the world's first genetically modified babies
Germline editing has already caused an international outcry
In 2018 a Chinese scientist announced he had edited embryos...
...using CRISPR to make them immune to the HIV virus
Two beautiful little Chinese girls named Lulu and Lala...
...came crying into the world as healthy as any other babies...
...a few weeks ago
He said that twin girls had been born as a result...
...who could now pass this immunity down to their children
As a father of two girls, I can't think of a gift...
...more beautiful and wholesome for the society...
...than giving another couple a chance to start a loving family
But the scientific community didn't agree
His experiment was seen as premature and dangerous
So, I think we still need to understand the motivation for the study...
...and what the process was for informed consent
The risks to these babies were enormous...
...and the potential benefits were really quite small...
...in a way that made it, I think, criminally reckless
He Jiankui was imprisoned by the Chinese authorities...
...and since then, there have been calls...
...for a global moratorium on germline editing
This could put the brakes on Denis's research in Russia...
...and he says he's keen to see more debate about editing embryos
While gene editing of human embryos is tightly regulated...
...the same can't be said about other areas
In some countries, fruit and veg in which specific genes...
...have been precisely edited aren't subject to the same regulation...
...as older genetically modified produce...
...which typically contain genes transplanted in...
...from some other species
And while the EU still bans gene-edited food...
...CRISPR produce can be bought in Japan and America
Some believe this comparatively permissive regulation...
...around gene-edited plants should give pause for thought
I don't know any country that I think...
...has a good regulatory structure for this
It's a lot easier to do wild experiments with non-humans...
...than with humans
Some of those will turn out to be good, useful
Some of them could turn out to be terrible
Some of them will turn out to be frivolous
But if we don't pay attention to them...
...we're likely to get lots of bad results
We need a better regulatory scheme
But advocates of the revolution in gene-edited foods...
...see numerous possibilities for improving production
This is the first start of our screening process...
...for our gene-edited bananas
Back in Australia, James is using CRISPR...
...to develop another disease-resistant Cavendish banana
So, we're setting up here the challenge protocol
These gene-edited bananas will contain no foreign DNA...
...and so won't be subject to the same strict regulation as his GM variety
He hopes they could be an answer to the looming banana crisis
We can take them out of field trials without getting any of those...
...sorts of permissions and can take them all the way through...
...to commercialisation which is fabulous
From tomatoes which might lower blood pressure...
...to mushrooms that don't go brown...
...gene-edited foods promise opportunities...
...for addressing the challenges facing global agriculture
The age of CRISPR completely changes...
...the way we think about agriculture
Perhaps the greatest benefit of CRISPR...
...could be in tackling the planet's biggest challenge, climate change
It is in making safe, nutritious, more climate-change-tolerant crops...
...for the world is where we really see as the future...
...of the biggest impact that CRISPR can make
And it's not just crops whose genes are being edited...
...to help curb global warming
It's animals too
This is Pleistocene Park...
...site of an audacious plan to bring back animals that lived here...
...tens of thousands of years ago...
...and in doing so, counter climate change
One of the more jaw-dropping is the woolly mammoth
A team of American scientists are working to recreate...
...the prehistoric beasts by applying gene editing to elephants
We've been trying to reduce the endangerment of the elephants...
...by reviving some ancient DNA variations found in mammoths
Scientist George Church hopes to use mammoth DNA...
...to create an elephant capable of surviving cold temperatures...
...to repopulate Siberia with these new animals
We're not creating a new species or a hybrid species...
...so much as rescuing Asian elephants
He hopes these animals could one day help control climate change...
...by trampling the snow and exposing the permafrost to freezing air...
...which should stop it melting and releasing greenhouse gases
If they're focused on the parts of the Arctic...
...that are richest in carbon and most at risk...
...then it can have an impact comparable to a gigatonne...
...of carbon dioxide per year
It's a bold claim and even if it worked as he suggests...
...its effect on the overall climate would be pretty small
Many worry that the headline-grabbing nature of projects like this...
...are diverting attention away from more pressing conservation issues
If it starts making people think of extinction as less of a problem...
...then I think that there could be severe worries
That said, in some ways, de-extinction and also the associated thing...
...of being able to, as it were, re-inflate gene pools...
...when things are close to extinct...
...I think that's very encouraging, the idea of being able...
...to bring back diversity that would otherwise be lost
Gene editing has the potential to transform life on Earth
And as scientists and society weigh the potential rewards...
...against the risks, there is a need to tease out what is simply...
...a fear of the new and what is a genuine ethical issue
Whenever you're talking about ethics and science...
...there is an innate tendency to see science running too fast...
...and ethics trying to pull it back
I do think there's also a need to look at what are the ethical things...
...you would like to see happen in the world...
...and how might science bring those about
Hello, I'm Tom Standage, deputy editor at The Economist
If you'd like to learn more about this topic, click on the link opposite
And if you'd like to watch more of our Now & Next series...
...click on the other link
Thanks for watching and don't forget to subscribe