Enigma Man a Stone Age Mystery Page #4

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new species Denisovans

in Southern Siberia but the

Denisovan DNA turns up in people

in Melanesia, Papua New

Guinea and areas like that

and appears on Australians.

The fact you've got

Denisovan DNA persisting

in modern day people means there

must have been interaction

between that kind of ancient

human and Homo sapiens

to get it in to our genome

at some point in time.

So the reason why you can have archaic

human surviving in other places too.

Since we know there was interbreeding

with ancient humans, perhaps

some of these features

are reflecting into breeding in the past.

Maybe in China, the same thing

could have been happening

with the Red Deer Cave people.

In terms of modeling, have

interbreeding happen,

I mean obviously we don't actually know

and it could range all the

way from peaceful encounters

where they traded with each

other and exchange mates.

That's one possibility.

The other extreme is a group

will run after the mates

and they will raid another

area and steal some women.

These encounters have left their mark

within us today, hidden in our genes.

There are suggestions that certainly

in the immune systems,

modern humans have picked up

some of the bits of DNA

from these archaic people.

So imagine modern humans evolving in Africa

coming into new environments

with new diseases,

new pathogens and so on.

By interbreeding with the locals,

they could get a quick fix

in picking up some of the

immunity which those populations

would have evolved over

hundreds of thousands of years.

Could the Red Deer Cave people

be hybrid offspring of modern

and ancient human parents?

Hybrids are really complicated question.

To diagnose a hybrid, you

need probably to have DNA

from Maludong and Longlin fossil

but also you need DNA from

both of the parent specie.

So, if we assume one is

us, one is modern human.

Who's the other species?

I'm not convinced that

interbreeding has been

unequivocally established.

It's an interesting idea

and I think there are some

compelling, maybe persuasive evidence

but it's far from open and shut.

To try to untangle the genetic origins

of the Red Deer Cave people,

Darren and Ji send samples

of the burned bones for DNA testing.

Ancient DNA science unlocked the genome

of the Denisovans from

their remains preserved

in an icy corner of Siberia

but the Red Deer Cave fossils

are a different challenge all together.

Fossil DNA is not easy to work with

because the bones have been

buried for many, many years.

So especially for this sample, they're very

nice, hot and readily humid

area so those conditions

are not good for ancient DNA storage.

Professor Su Bing is one of China's

leading geneticists.

A decade ago, he led the

team that mapped the DNA

of over 10,000 living East Asians

in search of their origins.

From this data, what we saw

is a very simple conclusion.

We all came from Africa, we

all have African ancestors.

But not all scientists accept

this genetic evidence.

There are those that promote what is known

as multiregional theory.

They believe that instead of

old members of our species

coming out of Africa, some modern humans

evolved out of Asia.

To explore this theory,

Darren and Ji traveled

to nearby Guangxi province.

Here amongst this spectacular

limestone landscape

lies Zhirendong, the mysterious

cave of the Homo sapiens.

In 2007, Professor Jin

Chang-Zhu and his team

unearthed two archaic human teeth here.

A year later, they discovered something

even more remarkable.

The primitive jawbone was

found to have some striking

and unexpected features.

A protruding chin is a

defining modern human feature.

When they dated the fossils,

they found they were over

100,000 years old but

the conventional theory

holds that the earliest modern

humans arrived from Africa

around 50,000 years ago.

This would mean that

modern humans were here

50,000 years before they

were supposed to be.

This is the heart of the

biggest controversy

in the science of human evolution.

The idea that modern day

Chinese are descended

from a separate evolutionary

line to the rest of the world.

In China, they believe that the Chinese

Homo erectus fossils are

their direct ancestors

and they can see in their interpretation

a continuative evolution

in terms of morphology

and behavior from a

million years ago through

to present Chinese populations.

I gave a talk there in the 1990s

on the Out of Africa theory

and it didn't go down very

well as you can imagine

and I was told that they

knew they were evolved

from Peking man.

It was almost like an act of faith.

I think they've demonstrated

that modern humans

got to East Asia much earlier

than the genetic evidence would suggest.

I think that's very important.

Ji believes that the Zhirendong fossils

are proof that modern humans

in this part of the world

evolved here in East Asia.

Whichever theory prevails,

Darren sees the find

as an important clue as to the identity

of the Red Deer Cave people.

What's impressed me about

the Zhirendong jaw

is that is does seem to

have a human like chin.

You don't see a human like chin

in the Red Deer Cave people jaws.

The Red Deer Cave people

don't look very modern

in comparison.

I think if Zhirendong do

represent an early modern

population then the Red

Deer Cave people can't be.

But the hunt for fossil DNA that could

confirm this has been unsuccessful.

Unfortunately we haven't

got any positive result.

We didn't get any DNA.

There's very little biological material

left in the bones and teeth from Maludong.

This is because they've been burned

to such high temperatures.

What it means unfortunately is

that there's really no chance

of getting DNA from them.

Despite the lack of DNA,

Darren is convinced

that the bones speak for themselves.

He's driven to the only conclusion

that makes sense to him.

After five years of working

on this big puzzle,

this conundrum, losing sleep,

traveling to and from China

to check and recheck.

I placed these fossils into what we know,

what we understand about human evolution.

I just can't see that they're anything

other than a new species.

It's an idea bound to create shock waves

throughout the scientific world.

Science is very conservative.

So when people find new things

that don't fit into current

widely held models where they

come up with new theories,

they're challenged, they're ridiculed.

Sometimes their careers suffer.

As soon as you make some announcement

that's unexpected, there's

always gonna be detractors.

I mean, why would there be a new species

of human surviving in mainland China

until be on the last Ice Age.

Yes, it's risky.

Of course it's risky but in a way

if you're gonna be honest

and true to science

then you've got to be

prepared to stand up and say,

"This is how I see the evidence."

It's a challenge to conventional wisdom

but then that's how science progresses,

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