These mosquito larvae in a lab at Imperial
College in London have been genetically engineered
to glow red under a laser.
But that red fluorescence is just a marker
-- It’s there to tell the researchers that
something profound has happened.
I ran out and I grabbed my supervisor
... I was like Tony but you know you've got
to look at this.
So we started going through and I read them
off one by one and I was like red, red, red,
red and we just...
It was a very crazy time.
We just started screaming and getting
super excited.
Since only one of their parents had a copy
of the red gene, you’d expect around 50%
of the larvae to be red.
But nearly 100% of them were glowing.
The researchers had hacked the rules of inheritance
with what’s called a gene drive.
But the red gene isn’t the point - it’s
been linked to a genetic tool that renders
female mosquitoes infertile.
And that’s a huge deal because this isn’t
just any old mosquito species.
This is anopheles gambiae,
one of the mosquitos that carries the parasite
that causes malaria.
So malaria is mostly a sub-saharan African
disease.
It affects people in the Indian subcontinent,
Southeast Asia, but it’s primarily a disease
of Sub-Saharan Africa.
And the majority of malaria deaths in any
given year in the world, hundreds of thousands
of deaths, are kids under 5 in Africa.
Over the past 15 years, there’s been a big
investment in bed nets, insecticides, and
better treatment.
And I think the result has been a lot of steady
progress on malaria.
That being said, it’s progress against a
really, really high death rate.
Most African countries really want to try
to eliminate it and WHO is really in support
of this, they’ve set some targets to achieve
in 2030.
And where we stand now, we don’t seem to
be on course for achieving those.
While researchers continue to work on a vaccine,
genetic approaches to malaria look increasingly
promising.
Genetically modified mosquitoes aren’t new
- a company called Oxitec has released mosquitoes
in Brazil that are designed to have nonviable
offspring.
But those don’t contain a gene drive, which
biases inheritance so that the modification
continues to be passed through a population,
though they can also be designed to have a
more local reach.
The idea of driving desirable genes into insect
populations dates back decades,
but progress toward that goal jumped ahead
after the invention of the CRISPR gene editing
tool in 2012.
CRISPR allows scientists make precise changes
to DNA in the lab.
A CRISPR gene drive could let them push those
changes through a wild population of insects.
It works by inserting the gene editing tool
itself into a chosen segment of the mosquito’s
DNA.
From there, CRISPR induces the cell to copy
the package onto the matching chromosome.
Like us, mosquitoes have 2 copies of each
gene, one from each parent.
And now that the gene drive is on both chromosomes,
it will get passed on to all the offspring,
where it will copy onto their other chromosome,
and so on.
So depending on what biologists attach to
that package, like the red fluorescent gene,
they can make some drastic changes to wild
populations.
There are two broad approaches to malaria
mosquitoes.
The team at Imperial College is part of an
international group called Target Malaria,
funded mostly by the Bill & Melinda Gates foundation.
And they’re aiming to use gene drives to
suppress mosquito populations.
Their drives are designed to spread female
infertility or to prevent females from being
born, with the effect of shrinking a population
of mosquitoes.
Then there’s a team of researchers at the
University of California institutions
who have been developing a gene drive that
alters, rather than shrinks, the mosquito population.
It spreads genes that make mosquitoes resistant
to the malaria parasite, so they don’t transmit
it between humans.
The World Health Organization has outlined
the steps that G.M. mosquitoes should go through
before being deployed. Gene drive research
is in phase 1 now,
but to find out if it could really work, they
need to test it outside of a lab.
And the researchers say their mosquitoes should
be ready for phase 2 soon.
I'm hoping the science is well within five
years.
Maybe even half that.
Maybe in one or two years.
A couple of years.
But then that's in the lab in London.
After something’s ready in the lab in London
you'd really want to go through very rigorous
testing.
So with every health intervention or technology
there’s kind of a spectrum of how much testing
and how much certainty people require before
they just try it.
This is always a trade-off in any medical
trial, if you develop a drug and it’s a
miracle and it helps everyone, when do you
stop the trial and just start giving that to everyone?
Once we have a gene drive that we can release
in the wild that could wipe out malaria, every
year we don’t do that is 500,000 to 700,000,
mostly kids, dying.
Kevin Esvelt the MIT scientist who’s working
on gene drives,
was talking to me and he said
Malaria is a case where there are really strong
ethical argument of doing something now today
because so many children have died just in
the time that we've been speaking.
I would say at least 20.
And his takeaway from that wasn’t let’s
do this as fast as possible.
It’s let’s do this right, because if we
don’t do this right, then there’s going
to be a massive backlash and we’re never
going to be able to do anything like this
ever again.
Yeah if you move forwards with a unilateral
“we are going to save the kids whether you
like it or not,” really does imperil
the broader malaria eradication effort.
Target Malaria has begun a lengthy process
of building facilities and staff in 4 African
countries, where they’ll be working with
non-gene-drive mosquitoes before importing the
gene drive mosquitoes.
And even then, there’s more lab work to
do before an actual release.
So the modified one is modified using a laboratory
strain.
So you have to do experiments to make
sure you incorporate the natural genetic background
of the mosquitoes in the area where you want
to work.
At each stage, they’re consulting with local
communities and with governments about this
genetic technology that’s designed to spread
across borders.
There are no regulators that have handled
this before.
Not only just in Africa, but anywhere.
I think i’m curious about you know this
notion that we have a public conversation,
we need to get people on board, this notion
that that would somehow lead to some clear
consensus or some clear green light.
At some point someone has to decide.
And I’m curious if you have a sense of who
that is.
Yeah, that’s the million dollar question
and no one I talked to even pretended to have
the answer.
The end game that got alluded to by a lot
of people was some kind of agreement by the
African Union about releasing a self-propagating
drive.
One tricky thing is malaria does not solely
infect people in democratic countries like
Ghana or Senegal.
It also affects people in the Democratic Republic of the Congo,
which despite
the name is a dictatorship. Countries with
really unstable and in many cases really awful
governance.
So one tricky question is, if the African Union
comes together and says yeah we’re ok with
this, is that legitimate?
Are they speaking for people in Africa?
And I think a lot the work that scientists
are doing is trying to reach out before that
and trying to start a conversation before that to make
sure it’s legitimate.
As the public debate begins, there’s a risk
that the politics of genetically modified
crops could spill over to the mosquito issue.
Anti-GMO groups like Friends of the Earth
have already called for a moratorium on gene
drive research. They fear it will be misused
by agribusiness and militaries and cause unintended
damage to ecosystems.
No one in this is as big of a son of a bitch
as nature.
Like, nature is so awful in every conceivable way.
It is completely indifferent to suffering.
But I think many of the things we look back
on as humans as our greatest achievements:
getting rid of small pox, penicillin, insulin
for diabetics, mass vaccinations.
Those are all things that involved messing
with nature and either repurposing or tweaking
things that nature created, for our own uses.
Some of the worst things we’ve made have
also done that.
But I look at the earth as something
we've  got to keep going for us and other
animals but I don’t look at it as this morally
benevolent place.
It’s a horror show that we’re trying to
manage as best we can and this is an ambitious
but really interesting way to manage it.
For a bunch more information about this fascinating topic,
go read Dylan's feature article on Vox.com.
I'll put a link in
the comments. And if you're interested in genetic engineering more broadly,
we have an episode on our Netflix show
called "Designer DNA," and it's about genetic engineering in human beings.
That's on Netflix, go check it out. Check out all the other episodes too,
we're publishing them weekly on Wednesdays.
