and dominant trees

in the Eastern United States Appalachian chain.

They were gorgeous trees.

It is actually the tree that inspired the Christmas song

"Chestnuts Roasting On An Open Fire".

It was a very heavily used resource by people.

In the late 1800s,

people brought Asian chestnuts to North America

as an ornamental tree, and they carried with them a disease,

a fungal blight and it infected

native American Chestnut trees

and just wiped them out completely.

Over 99% of the population was obliterated.

Fast forward nearly 100 years

and a team led by William Powell

at the State University of New York

was able to actually discover why the blight

kills the Chestnut tree.

And they have produced a strain of Chestnut trees,

that is 100% resistant to this fungal blight.

It really shows that there's no point of no return.

There's potentially no point you can get where you can't

end up recovering and healing the damage that's happened.

And that's the hope that biotechnology

brings to conservation.

The UN is issuing a dire warning on climate change.

Nearly a million species are at risk of extinction

because of humans.

We are doing irreparable harm to Earth's biodiversity.

And what is clear is that we're driving

species to extinction.

The human species has driven

the planet's biodiversity into an unprecedented decline.

The extinction rate is 1000 times higher

than it naturally would be

with as many as one million species at risk.

Many scientists say we are in a sixth mass extinction.

The decline in biodiversity is a crucial issue

that is largely overlooked in the public consciousness

in terms of how important it really is.

Our existence as humans is deeply intertwined

with the health and flourishing

of a number of non-human species.

If you destroy the environment,

it's going to turn around and bite back.

We need to radically rethink our relationship

to the natural world.

We need to understand that we are a deeply entrenched

part of it, certainly not separate from it.

This is part of what is killing other species,

and eventually us too.

Traditional conservation methods alone

are struggling to offset the speed at which

we're losing species and habitats.

Biotechnologies that have been developing in the wings

are now offering the hope of new, if not controversial,

ways of saving endangered species.

Genetic rescue traditionally has been the practice

of increasing a population's genetic diversity,

in a way to benefit it.

Usually when the population is exhibiting

some type of problem, like inbreeding or whatnot.

We're trying to increase genetic diversity

or increase the viability of the genetics of a population.

Then in that kind of very core definition,

biotechnologies offer a whole host of ways to do that.

Biotechnology offers everything from genetic insight

to restoring diversity with cloning

or technologies or doing gene editing,

to aid disease resistance, all the way to that moonshot

of using all those technologies to restore something

like a wooly mammoth or a passenger pigeon.

The process of resurrecting species like this

is known as de-extinction

and it's one of the more complex

and controversial applications of this biotechnology.

Because of biotechnology,

we can bring back those kinds of animals.

But of course it is a tedious work to do

but it is not impossible.

De-extinction is a scientific movement we could say,

an emerging space of researchers

who are trying to use a variety of different biotechnologies

in order to help recreate

close approximate versions of extinct species

so that they can create new animals

that mimic extinct species and can go back out

into the wild spaces where extinct species used to roam,

and carry out important ecological roles there

that have disappeared since a certain species went extinct.

The very first example of de-extinction,

if you call it that, is the bucardo,

which is a Pyrenean Ibex or kind of a mountain goat.

The last bucardo died in Spain, it was a single animal,

but they took some cells from its ear and preserved those.

And years later, they used those cells

to clone a bucardo using a domestic goat as the surrogate.

So they could create cells, implant an embryo in the goat

and the goat gave birth to a live Bucardo.

The species was brought back,

only to go extinct again just 10 minutes later,

due to lung defects.

The 2003 resurrection of the bucardo remains the closest

that anyone has gotten to true de-extinction,

at least for now.

In 2017, George Church's wooly mammoth project

captured the public's imagination

and brought de-extinction back into conversation.

So de-extinction is really just a little bit

of hybridization, using ancient DNA

and some modern synthetic DNA to achieve a goal

of say cold resistance or pathogen resistance.

Church hopes to adapt the genome

of the wooly mammoths closest living relative,

the Asian elephant, to include a number of mammoth traits.

In particular, how to thrive in the cold climate

of the Arctic.

We are using the tools of paleo genomics,

which is the ability to actually get DNA sequences

from those extinct species from 100s or 1000s of years ago,

and look at their genetic code,

compare it to their living relatives

and start to understand what are the unique fragments

of DNA that made them do what they did

in the environment.

Two, there's now something called gene editing,

which is most famously done with CRISPR Cas-9.

It's an enzyme and RNA combination,

that basically is a homing system that allows scientists

to target any region of DNA in a living cells genome

and make a cut and then make an edit to that area.

So we could take the hemoglobin gene

in an Asian elephants genome,

and cut it and overwrite in its place the hemoglobin

a wheel from a wooly mammoth, which will change

how it bonds oxygen at different temperatures.

And that's something that George Church's lab

has already done in culturing a Petri dish.

So it used to be a big deal to make one precise change

in the genome of an animal.

We've made 42 changes in pigs.

We now have 2000 adult pigs

that are called three point, version 3.0,

that are used for organ donations.

And that's being tested now in preclinical trials.

That shows we can do 42 in a cell and a lab,

and then move the nucleus into an egg

and bring it to term all the way to adulthood.

Thousands of times.

So we wanna do the same thing in elephants,

which are a little bit bigger than pigs,

little slower but otherwise it should be

a very similar procedure.

While altering the genome of living animals

like the Asian elephant could help bring a version

of extinct species back to life,

it could also help to rescue a species

which is itself endangered.

We want something that has all the advantages

of cold resistance, possibly resistance to pathogens

like the EEHV virus, that's almost extinction level

harm to the Asian elephant, which is an endangered species.

So you can consider it a hybrid

but it also, we can use synthetic biologies

to say alter tusk length to avoid poachers.

So there's a number of opportunities here

that is not limited to de-extinction of genes.

Church wants to re-introduce his hybrids

into the Arctic Tundra, which he hopes will preserve

an environment that's crucial to storing carbon.

Science has proven de-extinction is possible,

and the environmental argument for doing it is clear,

yet questions still remain.

Doing de-extinction, there's a whole lot of unknowns.

And especially when you're trying to think about a species

like a wooly mammoth

that's been gone for thousands of years.

What are the prospects for being able to put this back

in the appropriate kind of environment.

Does wooly mammoth habitat even exist anymore?

And if you go for very long extinctions,

the further back you go, the more uncertainty,

the less we know about the species

and the less likely there is to be a place for it now.

The technical ability is outrunning our ability

to think about is this a sensible or a useful thing to do.

And this is concern that, you know,

if we're dealing with something as fundamental

as the genetic makeup of species

and thinking about putting them back out into the wild,

you know, the genie's out of the bottle a bit.

What does it mean to take the tools

from synthetic biology and merge them

with the more traditional conservation biologists,

who are losing the game, as we're, you know,

also losing more species,

can really fruitful combination be born

from this hybridization of knowledge sets.

And indeed it seems to be happening.

There are interesting projects getting off the ground,

when you bring these two different ways

of looking at nature together, something that's engineerable

and something that's worth saving.