(light music)
- [Narrator] If you had the DNA
from a long-extinct species,
could you bring it back to life?
That's the premise for a number
of science fiction stories,
most notably the Jurassic Park franchise,
but the big problem here is
that DNA preserved in amber
for millions of years would
be so completely degraded
that there's really no way we could use it
to clone dinosaurs.
There is, however, another source.
The direct descendant of
some dinosaurs is still here,
walking the Earth, and as a
bonus, they're very tasty.
And this guy is trying
to see if it's possible
to turn chickens back into dinosaurs
by reversing the mutations
that changed them
from reptiles into birds.
- Yeah, yeah, but your scientists were so
preoccupied with whether
or not they could,
they didn't stop to think if they should.
- [Narrator] Yes, yes we
should, Jeff Goldblum.
Yes, we should, because
it just might allow us
to unlock the secrets that have been
stored in our own DNA for eons.
(dinosaur roars)
(dramatic music)
(chicken clucks)
Ever since mankind discovered
evidence of dinosaurs
deep in the Earth's past, we've wondered
what it would be like to share the Earth
with these giant beasts.
The answer, by the way, is bad.
Really bad.
(dinosaur roars)
Dinosaurs are big, and
they might want to eat you
and your whole family.
T-Rexes are basically just
murder machines on legs.
But in a way we do share
the Earth with dinosaurs.
- Let's think about birds.
- [Narrator] Yeah, birds are actually
direct descendants of dinosaurs,
and one of the oldest species
of bird is the chicken.
Remember this guy?
This is Arkhat.
He's a researcher at the Natural
History Museum in London,
with a focus on evolution and genetics.
- Oftentimes by understanding
how something is constructed
from scratch, how it's put
together during development,
can be very informative to explain
what happened during evolution.
- [Narrator] Chickens are an
extremely old species of bird.
They haven't evolved dramatically
since the Cretaceous.
That means we can compare
their genes to other birds
and understand what makes a beak grow,
or compare them to another
close relative, the crocodile,
and see what makes a
snout instead of a beak.
How different skull shapes compare
from one species to the next
is called the morphospace,
and by studying it,
scientists can get an idea
of how species have changed over time.
- It's a very useful concept
because it allows us to
meaningfully compare
the changes which occur,
for example, during development,
as an embryo turns into a juvenile,
turns into adults, or we
can compare, let's say
skulls of different species of animals
in the same three-dimensional morphospace,
and this allows us to understand
which parts of the skull
changed by how much,
and in which direction.
- [Narrator] And if there's
a gap in the fossil record,
they can sometimes predict
what sort of skull shape
would fit into it.
When you combine that with
an understanding of genetics,
you might be able to predict
what kind of mutation
would cause that change
in the morphospace.
(roaring)
In short, over time, you can find
the genetic changes that caused
those giant murder machines
to evolve into tiny, delicious chickens.
Arkhat and his team
analyzed the skulls and DNA
of a ton of species to get a sense
of what genes changed the
way the skull developed.
- To do this, we specifically
focus on the bones
which make up the snouts
and the beak in birds,
and we looked at the
shape changes over time,
over evolutionary time, and
we realized at some point
that there's a gap between
the part of the morphospace
which is occupied by animals with snouts
and modern birds, which all have beaks.
- [Narrator] It turns
out what makes a beak
is actually a pretty identifiable gene,
and by blocking how
that gene was expressed
in the facial development
of a chicken embryo,
Arkhat and his colleagues
were able to produce
a chicken embryo that developed
a snout instead of a beak,
exactly as the morphospace predicted.
- The morphospace predicted
that this gap will be filled,
that these shapes are possible
by gradually changing the amount
in the middle of the face,
we're able to gradually transform the face
back into its more ancestral condition.
- [Narrator] Lots of other researchers
are looking at wings,
tails, feathers, et cetera,
to understand how each characteristic
is controlled by genes.
The combination of all this knowledge
is like unlocking the source code for DNA.
Eventually we might be able to map
how the wildly complex
set of instructions in DNA
results in the amazingly
sophisticated biology
that is all around us.
Chances are, unless there is
an eccentric billionaire out there
with a spare island to dedicate to it,
we're not going to be turning chickens
back into T-Rexes any time soon.
- Yes.
- But in the short term, this research
will contribute to practical applications,
like genetic engineering
for better livestock,
and it could also help treat
human developmental disorders.
The DNA that built dinosaurs,
megalodons, and all the other crazy things
we see in our past, it's still here,
preserved and passed down
by the very process of life itself.
(dramatic music)
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and changing the world.
(dinosaur roars)
