All language subtitles for Royal Institution Christmas Lectures 2013 s01e02 Am I A Mutant.eng

Hello, is that the chief keeper of the
zoo?

Yes. Ah, it's Charles Darwin here.

Hello. I've written an exceptionally
good book and I'm having a party to

celebrate it. Oh, yes. And I'd like to
invite some of my relatives.

Of course, yes, relatives. Right, good.
Now, I want to invite Miss Fish.

Fish. Mr Worm. Mm -hmm.

Mr and Mrs Mole Rat. Mole Rat, yes.
Master Parrot Esquire. Mm -hmm.

Oh, yes. Are they relatives?

Well, yes, of course they're my
relatives, because they are.

Oh, by the way, could you possibly get
me some tickets for the Royal

Christmas Lecture? Of course, yes.

mutant in the audience?

Ah, here we are.

What is wrong with you? Would you like
to stand up?

You've got something horrible wrong with
your head and you've got funny little

tendrils coming out of your chin.

What does it feel like in there?

Oh, horrible.

Horrible. A bit smelly. Yeah. A bit
smelly. Thank you very much. Do sit

Are there any other mutants in the
audience?

Oh, look at you.

What's wrong with your ears?

Well, they're a bit large.

They are a bit large.

Can you hear well with them?

Fine. Fine?

They do look a bit strange, though,
don't they?

Yeah, they're a bit pointy. A bit
pointy. Yeah. Are there any other

the audience?

Well, you don't look that mutant to me,
but we'll come and have a better look.

Oh, I've just spotted something.

There's somebody over here with
particularly unusual feet.

Oh, good heavens. What happened to you?

Were you bored like it?

Yeah. Oh, what are they like?

They're interesting. They're so much
fun.

Are they? What can you do with them?

Oh, you can climb up walls.

Haven't you? We've gone to so many
different things. How useful.

Goodness me. So, any other mutants in
the audience?

The odd friend being pointed out. Does
that mean the rest of us are all the

same?

No, look around.

There's a huge amount of variety in this
audience.

We've got different colour eyes, we've
got different lengths of hair and

different colour hair, we're all
different shapes and sizes.

Well, the reason for that, ladies and
gentlemen, is that we're all mutants of

one sort or another.

Greetings, fellow mutants. Welcome to
the 2013 Royal Institution Christmas

Lectures. I'm Alison Woollard, and today
we're delving deeper into Life

Fantastic to reveal how the
extraordinary sciences of developmental

genetics can explain not just why the
human race is so beautifully diverse,

why there is such stunning diversity of
life on our planet and precisely how it

all came to be.

But to do so, I'll need a special
assistant of the four -legged variety.

Welcome.

You're a beautiful dog.

Gosh.

So what are they called?

This is Tosca the Blue Great Dane. And
this is Cookie.

And Cookie.

Goodness me.

And are they friends?

Do they get on well together?

They do. They get on very well together.

Yeah. Gosh.

She's the boss. The little one's the
boss.

Would you like to go and show the
children over there? Yeah.

Come on in. You can have a little look.

They're very gentle, don't worry.

So what is it that makes a Great Dane a
Great Dane? What features do you look

for? Well, she's actually really, really
small for a Great Dane. Is she? They

can be sort of six, eight.

Ten inches taller on the shoulder than
she is.

And what about the little one? Oh, she's
typical Mexican -blooded, fiery,

aptitude -y, very loving, very loyal.

So, for thousands of years, we humans
have been breeding mutant dogs.

They have a character that's useful to
their human masters.

She's taken a shine to me, I think.

Yes.

What were Great Danes originally bred
for?

Originally, they were dual purpose. They
were bred to hunt wild boar and to be

dogs of the noblemen. And what about the
Chihuahua? What were they originally?

They were bred to be ratters and
companion dogs.

Gosh. Because they're very affectionate
and do love a cuddle.

And the characteristics we see here in
these dogs are caused by mutations.

And because we humans select the mutant
characteristics we like the most when we

breed dogs, it's these characteristics
that are passed down through the

generations and these beautiful breeds
will carry on.

Jane, thank you so much for bringing
your dogs to show us today. So

we humans have created extremely diverse

form in dogs according to the ones we
take a fancy to. But they're all the

species. A dog is still a dog.

Indeed, at the DNA level, they're
remarkably similar.

It turns out that the difference in fur
type of dogs, so the coat length and

whether or not the coat is curly or
straight, that's caused by mutations in

three genes in the dog genome.

Well, I've said mutation. What is a
mutation?

To reveal this, we need to go back where
it all begins, with DNA.

This molecule is the stuff of life, the
most amazing thing, the foundation of

everything. And we find it inside the
nucleus of every single one of our

The thread of life itself, beautiful in
its very simplicity.

There are two long chains of letters, or
what we call bases, made up of

nucleotides, of which there are four
types.

Adenine, guanine, cytosine.

and thymine, A, G, C, and T.

And the bases connect together by simple
rules.

A always base pairs with T, and C always
base pairs with G.

And the overall shape of the DNA
molecule is therefore a double helix.

The bases within DNA are the code upon
which all life forms in their infinite

diversity are made.

Long strings of these bases make up the
instructions for one particular

characteristic, like a short -haired
dog, a gene.

And the code is passed on faithfully to
all cells in the body because every time

a cell divides, its DNA has to make a
complete copy of itself and then divide

those two copies precisely equally
between the two daughter cells.

Now this is a pretty remarkable feat.

Because it turns out that inside our own
cells, our DNA would stretch about two

metres if it was fully unwound.

And all that DNA has to be replicated
every time a cell divides.

The structure of DNA provides a big clue
as to how this might happen.

In fact, James Watson and Francis Crick
commented on this.

when they published the structure of DNA
60 years ago. And coming on now,

Charlotte, a curator at the Royal
Institution, has something rather

show us.

And this is an original copy of Watson
and Crick's paper on the structure of

in the journal Nature.

And I'm going to read you the last
paragraph because this is my favourite

It's not escaped our notice, they said.

that the specific pairing we have
postulated immediately suggests a

copying mechanism for the genetic
material.

Thank you, Charlotte.

Well, shall we see what they meant with
the help of Infinity Elite?

Our acrobats are colour -coded according
to which nucleotide they represent.

And they're going to form a human DNA
strand.

Okay, so they're going to obey the rules
of base pairing.

G and C at the bottom pairing together,
so holding hands.

And then T and A pairing together, so
holding hands.

And at the top, G and C holding
together, pairing hands.

So we've got a strand of DNA made up of
three bases on each side.

Now, this molecule is going to
replicate.

So the bonds will break, and it's a bit
like the DNA molecule unzipping.

And then, going to turn, and new
nucleotides are going to come in, and

going to bond with their partner in the
way that the bases would. So again, G

pairing with C, A pairing with T, G
pairing with C at the top, they've

their bonds, and now we can see we've
made two DNA strands, two DNA molecules.

Absolutely original to the first
molecule.

Okay.

Thank you very much. Please come down
now.

Ladies and gentlemen, infinity.

So now we've seen just how simply and
easily DNA replicates.

Let's think about when this happens.

It happens every time a cell divides.

Every time any cell in your body
divides, all your DNA, all two metres of

enough, your whole genome is replicated
too.

So let's see this happening in a real
cell.

And what we can see here...

are long molecules of DNA called
chromosomes.

So in our cells, we have 23 pairs of
chromosomes, and the chromosomes hold

genome, all of our DNA, in these long,
linear molecules.

And when a cell divides, these
chromosomes replicate themselves, so all

gets replicated.

And then the pairs of chromosomes sort
themselves out and get divided precisely

equally between the two daughter cells.

And we're going to see this happening
now as we play the video and this cell

divides. So you can see those
chromosomes have split first absolutely

and then finally the whole cell divides.

And so we end up with two daughter
cells.

That's a remarkable feat for a cell to
do.

What if the system isn't so perfect
after all?

What if mistakes creep in?

They needn't be big ones, just tiny
ones.

In fact, Kim just knocked a base off
there when she was leaving the room.

So what happens if a base gets deleted
like this, falls off?

Or one base is substituted by another
like this?

Well, that's not right.

That's a mistake.

That would be a mutation.

A mutation is a change in a DNA
sequence, a change in the instruction

making an organism.

Now, what difference does a change in
just a few letters make?

Shall we find out?

Can I have eight volunteers, please, to
play a game? Right. We'll have you and

you and you two there. Yep. And you
and...

And you, how many sat? Come down to the
front, that's it, come down.

We've got our eight.

One, two, three, four, five, six, seven,
eight. Now what we're going to do is

we're going to play Chinese whispers. So
we're going to start off with a

sentence that I'm going to tell Kelly
here.

And she's going to pass it down the line
and we're going to see what we get.

So for us then, in this demo, a sentence
represents an instruction that DNA

gives a cell.

And each whisper represents a
replication.

A division of the DNA.

Okay? So should we run the experiment?

Can you see the message?

Got it?

Okay, so pass it on down to your friend
here.

Keep going.

Going down the line.

Oh, I think they're very good, these
people.

What did you get?

A loud thing is a key.

A loud thing is a key. Are you sure?

Is that what you told her?

A loud thing. What did you tell her? A
loudie. A loudie? Yes.

What did you get?

What did you get?

Allow me a key.

Oh, goodness me.

What about you?

A loud key is a key. What did you get?

A loud key is a key. A loud?

I thought a loud key was a key. Zab!

Well, we started off with the lab P was
the key.

So what happened?

She told me it was Zab P.

And you passed it on?

Yeah. Just like a mutation would.

And then we got to you and we suddenly
got a loud, didn't we?

And then goodness knows what happened
when we got to the end.

But can we see that what we've ended up
with then...

is a system where mistakes might have
occurred at every whisper. And it seems

our system that mistakes have occurred
at almost every whisper, doesn't it?

And sometimes you can get several
mistakes happening at once.

And I think there was a bit of that as
well. We just don't know.

But what we've ended up with is a
message that bears some resemblance to

message we started off with. But it's
completely changed in meaning, hasn't

You were brilliant. Thank you so much.
Do go and sit down.

language of genes then a mutation could
change the characteristic of the cell

and thus in turn the whole organism once
the mistake occurs in a DNA molecule in

a cell it will be passed from every cell
produced from that cell to its

daughters and so on and so on down the
line in fact mutations are happening in

our DNA all the time Some of you sitting
there probably have DNA molecules that

are getting mutated as you're sitting
there listening to this lecture. It's an

alarming thought, isn't it?

Don't worry too much. Cells do have
quite good ways of dealing with some of

these mutations.

But when does it matter most?

What kind of cells does it really matter
if you get a mutation in?

And the answer is it matters a lot when
it occurs in a very special kind of cell

indeed, a cell called a gamete.

So gametes are eggs and sperms, the
cells that unite to form a whole new

organism, the next generation.

And we can look at some gametes,
actually, because we've got some gametes

going to show you in a video from my
favourite animal. Does anyone know what

animal this comes from?

Yes.

Worms. Yes!

How did you know that?

You were here, you're very clever, yeah.

Heard quite a lot about worms, haven't
we? So this actually is an egg cell

that's just become fertilised by sperm.

And we should see these nuclei closing
on each other, the cells sort of

encouraging it to do that. There we go.
That point of fusion is the point.

at which that egg becomes a zygote, and
that will then become an embryo and a

whole new worm. And if a mutation has
happened in either that egg nucleus or

that sperm nucleus, then there's the
capacity for those mutations to be

on to the next generation, so for those
mutations to be inherited.

So what are the rules of inheritance?

Who gets what, why, and how?

and the rules were worked out by an
Austrian monk called Gregor Mendel, long

before DNA or even chromosomes were
discovered.

What Mendel did was he traced patterns
of inheritance through many generations

of pea plants. He looked at particular
varieties of pea plants that looked a

particular way. You can see here, this
one's got white flowers.

And he was the first proper geneticist.
We call him the father of genetics.

And what he did was to carefully
quantify all his results to come up with

very simple rules of inheritance.

And what he found surprised many people.

We're going to look at it now in more
detail.

Now what I've got here are two jugs of
paint.

One blue and one yellow.

And these could represent two flowers.

or two animals, or two of anything
that's going to mate together and

offspring.

So can I have a volunteer who doesn't
mind getting slightly messy? I think you

look like the sort of person who doesn't
mind getting slightly messy.

Now, would you like to tell us your
name?

Leifan. Sorry?

Leifan. Leifan, right.

Now, we're going to put a little apron
on you, and you've got some safety

glasses there.

Now, I suggest we pour one. It doesn't
matter if we make a mess.

Okay. We'll pour one jug in here.

Okay.

Oh, it's very gloopy, this paint, isn't
it?

Right. I think that'll do.

And now we need some yellow.

Right.

Very good.

Excellent. Now, I think we need to mix
them a bit, don't we?

Are you any good with a mixer?

Ah! What do you think? Shall we give it
a go?

Yeah, let's give it a go. Right.

There you go.

Flick the switch.

Maybe you want to go slightly that way.
Oh, dear.

Let's turn this off again, quick.

This hasn't been set up very well, has
it?

This has obviously been put together by
some sort of boy.

Let's go for it.

Ooh, my goodness, please.

How are we doing?

Good mixing, good mixing, right.

Right.

What have we got?

Green. Yes, we've got green.

So when we mix together the blue and the
yellow, we've got... We've got blue

and yellow everywhere.

And we've got green.

That's brilliant. Thank you so much.
Now, just before you go, can you get the

blue and yellow back from there?

No, no, no.

But do you think it would be possible to
get the blue and yellow back from the

green? No.

I wonder why.

Because they're mixed.

Blended. We can't get them back again.

Oh well, they'll just have to stay
green, won't they?

Thank you so much for coming back.

Now, that is exactly what Mendel
expected to happen, right?

When he crossed his pea plants together.

That's what everyone at the time
expected to happen.

But actually that's not what happened.

That's not what Mendel found.

Mendel's characteristics in the pea
plants don't simply blend.

So what did happen?

Well, we need to look at it a slightly
different way.

Thank God there's no more paint.

So imagine instead of paint to represent
our reproducing species, we instead use

these balls, okay?

So we've got a blue parent over here,
and we've got a yellow parent, and

in a box, and the box is meant to
represent our organism, okay?

So you need to go with me on this one,
suspend your disbelief a little bit, but

let's just imagine that these two boxes
of balls fall in love, and they decide

to reproduce, right?

So I'm going to mix their genes.

A box in the front, okay?

And I'm going to give them a bit of a
mix.

Like this.

Now, can anyone see green progeny?

No. If you scrunch up your eyes and you
look at this very quickly, what do you

see,

blue or yellow? What do you see more?

What does it say?

Blue. Blue, yes.

So we've still got these little yellow
balls in the organism, haven't we? But

the blue colour is dominating.

You agree with that?

Yes? Good.

Thank goodness for that.

So that's one generation.

Now what's going to happen when this
little fella reproduces?

Do we find out?

And this time there are various
outcomes.

genetically speaking.

So shall we see what's going to happen?
Now remember, we have to get an equal

share of genes or traits from mum and
from dad.

So we've got mum here and dad there, or
I don't know, is it dad here and mum

there? I can't tell the difference with
boxes of balls, it's hard to tell.

Right, so what we've got here, we've got
two offspring that look very much like

the parents, okay? The blue colour,
again, is dominating in these.

progeny. But there's two other kinds of
offspring we can get. We can get one

where they only inherit the blue genes
from mum and dad, all right?

And a few extra ones.

And what's that going to look like?

Blue, yeah, pure blue.

And then this is the interesting bit,
right?

We can get ones that only inherit the
yellow genes from both mum and dad,

a few extra.

I don't know why you're doing that.

So what will this one look like?

Yellow, yes, yellow.

Now, it didn't have any yellow parents,
did it?

But it did have a yellow grandparent.

Now, do any of you look more like your
grandparents than your parents?

Yeah, somehow I do. I think I do look
more like my grandmother than my mother.

So this yellow...

Well, this yellow characteristic has
skipped a generation, right? But it's

back. It's been preserved. It hasn't
been blended.

The offspring aren't just a mixture of
the genes from both parents.

And that's what Mendel found.

Inheritance is not blending at all, but
particulate.

We would call the yellow characteristic
or form of the gene recessive and the

blue one dominant.

So if... Blue and yellow, if we have
both blue and yellow in our progeny,

the blue one will dominate and that will
give us the colour. But if we've only

got yellow on its own, then that gives
us the yellow offspring.

So Mendel's was an amazing finding,
especially as it was over 40 years

anyone actually coined the term gene.

And another 40 years or so before the
naming of the molecule of inheritance as

DNA.

But Mendel's findings were largely
ignored at the time.

Because, I don't know, he was a monk,
hidden away. Maybe he wasn't very good

PR.

So I think what we need to see now is an
example of Mendelian inheritance at

work in a real animal.

And I need to welcome Pippa here.

With your lovely cat.

So what kind of cat is this?

Oriental. An oriental. Gosh.

And what's the name?

Nellie. This is Nellie. Gosh.

And I understand that Nellie's been
doing a little genetic project all of

Oh, is this Dad?

This is Dad.

This is Dad. What's Dad's name?

Giddy. Giddy.

Oh, beautiful. Different colours. Both
got some short hair.

And I understand that they're just like
the boxes.

And they've been doing a little genetic
project all of their own. They have. And

I think if we're lucky, we may even be
able to see their babies.

Look at these.

Goodness me, I'm going to have to have a
little hold.

And this one, this little baby here, has
got long hair.

Yes. So we've got, how many kittens have
we got all together here? There's

eight.

Eight. And when were they born?

They're 11 weeks old.

Oh, aren't they gorgeous?

They've got gorgeous ears.

And how many of them have got long hair?

Three. Three long hair and the rest are
short hair, just like mum and dad.

And so this is very much like the balls
that we were looking at before, isn't

it? So the long -haired kittens would be
like the yellow, the yellow -balled

organism. And the short -haired kittens,
calling for mum, the short -haired

kittens could be like the blue or the
mixture of the blue and the yellow. Can

keep one?

Absolutely gorgeous.

And, of course, the other thing we've
got going on here is the assortment of

these coat -colour jeans, haven't we?

so we haven't just got the long and the
short hair going on we've oh we've

actually got the colors being assorted
as well aren't they absolutely gorgeous

well thank you so much for bringing and
thank you thanks dad and mum thank you

so much for bringing your lovely pack
now it

was the variation that exists in our
domestic animals especially in dogs and

cattle, that caught the eye of a young
naturalist called Charles Darwin.

Darwin became quite interested in the
variation in domestic animals.

And then when he went travelling abroad,
he noticed a similar thing happening in

the wild, and he called this adaptation.

And Darwin sailed to the Galapagos
Islands off the coast of South America.

And while he was there, he noticed
different varieties of finch.

We've got some up here.

living on the different islands.

And Darwin noticed that each species was
perfectly adapted to its particular

environment, as the environment varied
slightly from island to island.

In fact, the voyage that Darwin went on,
on HMS Beagle, was probably the most

important voyage ever in the whole
history of life on Earth, because it led

completely revolutionary idea, natural
selection.

And here, ladies and gentlemen, for the
very first time in the history of the

Royal Institution, to tell us about his
great idea, probably the greatest idea

in science, please welcome Charles
Darwin himself.

Hello? Hello?

Is this box working?

Yes!

future. Can you hear me? Yes.

Good evening, Dr. Moulard.

Good evening, ladies and gentlemen.

Oh, call me Alison, Charles. Are you
okay in there? Looks a bit of a squash.

Yes, yes.

You've got me trapped like one of my
butterflies or pinches, haven't you?

Yes. It's quite fun being a specimen for
a chain.

Yeah? Do you know where you are,
Charles?

This is the Royal Institution Lecture
Theatre.

Oh, didn't you?

But it's jolly splendid doing it from
the grave.

Oh, now you're here, perhaps you could
tell us something about your theory.

Maybe just in one or two sentences,
though.

Yes. Yes.

Yes, well, descent by modification and
by

means of natural selection. That's it in
a nutshell.

Variation of...

you mind if we did a quick experiment to
test your theory?

Well, that's fine by me. Oh, good.

So that I don't have to take part. No,
no, no, no, no. I'd love to have a chat

with that mingle chappy.

Oh, yes.

in series and for this I need eight
volunteers I need four girls and four

okay so we'll have you two we'll have
you and you and we'll

have we'll have you and you

now you are all going to be predators
and you're going to compete with each

other do you like competition good

You're going to compete with each other
for the most important thing in life,

which is what?

Food. Food.

Excellent. And you're going to compete
for the most important kind of food

to children, which is? Sweet food.
Sweet.

Exactly.

But you're all going to start off a
little vertically challenged.

So I'd like you to all kneel down,
please.

Right.

Now.

I'm going to make a very unlevel playing
field at this point.

You're all going to have different
mutations.

You've all got a mutation that's made
you rather small, right?

But you're going to have different
mutations that's going to be beneficial

some of you and harmful to others.

It's going to affect the way you can
compete for the food, right?

So you two are going to stay kneeling
down. You're not going to have a

that makes you tall.

You two, on the other hand...

are going to have a mutation that makes
you nice and tall, so you can stand up.

Okay. Very nice and tall.

You two are going to also have a
mutation that makes you nice and tall,

can stand up, but you're going to have a
mutation that affects your hands and

makes them not very useful.

So we've got some boxing gloves for you
to put on. See?

If you'd like to put your boxing gloves
on as best you can, your assistants will

help. You two are going to have a
mutation that makes you nice and tall,

So stand up, but you're going to be
blindfolded.

So your mutation is that you're not
going to be able to see anything.

Now, I think we have a carer.

Serena behind is going to be health and
safety.

Right, now we have an environment here.

that is meant to represent a jungle
canopy with sweets hanging down quite

high up, okay?

And what you're going to do is you're
going to compete to get as many sweets

you can, and the winner is the person
with the most sweets.

There's some rules here. The first rule
is you mustn't be polite.

Or say please or thank you or excuse me.

Right, competition in the wild is about
using your elbows, pushing other people

out of the way and doing whatever you
can to get your food.

On your marks, get set, go.

Ten, nine, eight, seven, six, five,
four,

three, two, one.

Okay, stop,

stop, stop, stop, stop, stop. Let's see
what we've got.

Right, come forward.

Oh, what are you sharing? That's nice,
isn't it?

I don't think you would in the wild,
though.

Well, you can take your blindfolds off
now.

Probably a mystery, this whole game,
isn't it, when you've had a blindfold.

You can see what you would have been
doing now if you'd had a chance to look.

So what happened? What did you get? How
many did you get? Nothing.

Nothing at all?

Not one?

Not even one?

Couldn't even feel one?

No. Nothing?

Oh, dear.

What's going to happen to you?

You're going to die.

There's no easy way to say this, mate.
You're going to have to go and sit down.

You're dead.

Sorry. Thank you very much, mate.

What was the problem with you guys? You
had hands. You could see. What's going

on? No grabbing.

That pesky mutation, isn't it?

Stop your grabbing.

So what's going to happen to you two?

You're going to die.

It's tough out there. You'd better go
and sit down.

You'd better go.

You two have rather an interesting
result.

Because you didn't cheat, did you? No.
So how did you reach the suites? They

were very high up.

You did a bit of jumping.

My knees hurt though. Do they?

But that you adapted a little bit,
didn't you? You evolved the ability to

a bit.

What about you?

Long arms.

Long arms. You stretched your arms so
much that...

Well, you've done okay.

I mean, you've got a bit of food there.
I mean, I'm not saying that you're going

to survive long term, but for now, you
know, you're there for another few

Thank you very much for taking part. And
you can eat your sweets when you don't.

I'll do more. Let's have a look at what
you've got.

So what are you going to do with those?

Not much.

You don't like sweets?

You're going to eat them. You're going
to eat them, are you?

And then what's going to happen?

We're going to live off them.

We're going to eat some more.

We're going to be happy.

We're going to live a nice, good, long
life.

Do you think, um... Do you think you
might... I mean, uh...

Do you think... Have you ever thought
about... Having a baby?

Not yet.

Well, obviously not with him, but with
someone like him.

Yeah? And if he did do that?

What would your children look like?
Would they be good at getting food as

They would, wouldn't they?

So your genes would reign supreme. You
would win in the evolutionary race.

Ladies and gentlemen, our winners are
naturally selected.

Thank you both.

I just want to have one last look at
this environment before...

We put it away.

Because I don't have it so high up. I am
very small, you know.

I can actually find some sweets here
that nobody noticed.

They're all over it. Everybody picked
red sweets.

Nobody picked these dark sweets.

Now, why was that?

Yeah.

Yeah.

It evolved to live, to be there. Yes.

Yeah, there's a little bird I'm looking
for here.

Camouflaged! Excellent. So our predators
evolved, and the most successful

predators were the ones that were best
evolved to grab the sweets.

But our prey had some evolution in them
as well, didn't they? So our prey were

best adapted to survive if they don't
get noticed.

So when we think about natural selection
in environments, we can think about

that acting in lots of different ways,
on lots of different levels.

Okay.

Thank you, environment. I think it's
time to go.

The idea was that organisms change very
gradually over time.

Eventually they might gain or lose a
limb, an eye or a wing.

We now know that this change is caused
very, very gradually by mutations in DNA

molecules that are inherited.

So you see...

Ultimately, one type of creature can be
transformed into something completely

different.

Darwin was galvanised into publishing
his great work on the origin of species

1859. It was a bold and brave idea,
causing a storm in Victorian society.

But it's still impossible to overstate
the importance of Darwin's great idea in

biology today.

In illustrating his theory of evolution
by natural selection, Darwin realised

that all species are connected.

Indeed, they share a common origin.

He thought of the concept of the tree of
life.

Darwin's tree was a simple one and we
now know it to be much more complex.

But nonetheless, Darwin was right.

Life started with simple life forms.

4 billion years ago.

And then natural selection has sent
organisms off in a myriad of different

directions to make the diversity we have
around us today.

And all this present -day diversity and
all the millions of animals that evolved

and didn't make it descended from common
ancestors some 4 billion years ago.

This means everything is related to
everything else along a complex tree of

life. What would Darwin think of the
beauty and complexity of the tree of

as we know it today?

Shall we ask him?

Hello. Oh, hello.

Am I on again? Yes, you are.

Am I? Yes.

Wretched machine. I know.

Right.

What you want to know is what I think
about all this. Yes.

I like this bit.

It really is very dramatic. I know.

There's grandeur in this view of life.
Oh, yes.

It's several powers.

Having been originally breathed into a
few forms or into one, that whilst the

planet has gone cycling on according to
the fixed law of gravity, from so

simple a beginning, endless forms, most
beautiful and most

wonderful, have been and are being
evolved.

Oh, yes, very much. I think I'll put
that in my book. Definitely.

But tell me, dear lady, there is one
thing that

vexes me.

What happens inside the bodies of these
creatures to change

according to my theory of evolution?

Well, good question. Ladies and
gentlemen, I give you...

Charles Darwin.

Now, Darwin didn't know what you're
about to find out.

He lived in an era before anyone coined
the term gene.

In fact, he died over 60 years before
DNA was even named.

And we can't possibly tell him now, can
we?

Let's think about Darwin's question
then. How does all this change come

Well, it all starts with DNA. So let's
look at that.

You'd expect that with all this huge
variety that there would be huge

differences in DNA, wouldn't you? From
worms to bats, fungi to whales. Well,

scientists can sequence all the DNA in
cells of a particular species, its

genome, very easily.

We can do lots of comparisons.

Let's see what we can find.

Can I have two volunteers to help,
please?

I'll have you two there.

Thank you.

You can come and stand here.

That's it.

One on either side. Now, we've got...
You're not frightened of animals, are

Good. They're not spiders, I promise.

Wouldn't allow them to have spiders.

Now, we've got some animals in front of
us and we're going to find out what they

are, OK? So why don't you lift the lid
on this one and we'll see what we've

Oh, look!

What's that?

It's a rat.

It's a rat.

Very good.

Now, what about you? Are you going to
lift the lid on one of yours?

Oh. Well, now, what do we think these
are?

Fish. They're fish.

Have a quick...

Have a good look at them.

Something very strange about those fish.

They don't have any eyes. They don't
have any eyes. Very good. You're very

observant, aren't you? They are blind
Mexican cave fish.

They live in caves full of bat poo,
apparently.

And that means that over the years
they've given up with the need for eyes.

They've acquired mutations that mean
that they don't have any eyes anymore

because they don't have any need to see.

They're our Mexican cave fish.

This one's very quiet, isn't he? Ah,

the chimp.

Now what we're going to think about is
we're going to think about some genome

sequences from these organisms that have
recently been published.

So we've actually done a bit of work.

And we've looked at the DNA sequences
that is the DNA sequence of all the

of all these three organisms that have
been compared.

With our own genomes.

So we've got three numbers. Can we see
those? We've got three numbers for each

animal. So for the chimp, we've got 85%,
92 % and 97%. Now which one do you

think applies to the chimp? How related
is the chimp to us?

85, 92 or 97?

What do you reckon? Probably 97.

97? What do you think? Seems an awful
lot, doesn't it?

I think 97 too. You think 97 too?

What does the audience think?

You think lower?

So who thinks lower?

No one?

Right, well, we'll put the 97 in there.

Okay, 97. Now, the next one, the cave
fish.

Right, we have three scores here, three
percentages. We have 21%,

41%, and 61%. 21%. You reckon? Yeah,
21%.

Right, put that one there.

Okay.

And the last one, what have we got? Oh,
gosh.

89%, 79 % and 49 % for the wrap.

So which one are we going to go for?
Maybe 79%. 79 % in the middle? What do

think?

I think 49%. You reckon 49%. We're going
to have to ask the audience on this

one, aren't we? Who thinks? Hands up for
49%. Hands up for 79%. Oh,

it's an outright winner, isn't it?

79%. Right, 79. I think our little rat's
settling down for the night now.

So let's see how you did.

Actually, pretty well.

And you were spot on with the chimp. So
the DNA of the genes of the chimp are 97

% identical to our own.

And you were spot on with the rat.

So the DNA of the genes of the rat are
79 % identical to our own. Isn't that

amazing? Because, I mean, I don't know
about you, but...

I don't feel terribly rat -like. Well,
sometimes I do.

And the cave fish, you were a little bit
of an underestimate on.

Okay, so it's actually more like 41 % of
our DNA

is identical. The G of our genes is
identical to the genes of this blind

cave fish.

I think that's quite surprising, don't
you?

Thank you very much for helping me.

Wait a minute, though. Wait a minute.

There's a problem here, isn't there?

If everything is so similar, how come
everything is so different?

How come we look incredibly different
from the rat and the cave fish and the

chimp? The answer, as we shall see, lies
not just in what genes we have, but

whether or not these genes are even
switched on.

In fact, let me tell you a story.

Here in British Columbia...

There's a lake, there it is, that
contains a creature that really

there at all.

A bit like this. These are sticklebacks.

Most sticklebacks are marine. Most
sticklebacks live in the oceans.

Here's a marine stickleback.

and what marine sticklebacks have are
these very well -defined pelvic spikes.

So on their underside, they have these
very prominent spikes, and they use

spikes for defence, because when you
live in the ocean, you have some very

-looking predators.

But some 10 ,000 years ago, a few got
left stranded in the lake, and something

incredible happened.

We have a picture of a lake stickleback
here.

Now, can you spot the difference?

With these sticklebacks. Yes, what would
you say?

There's no spikes.

Yeah, we can see a few other differences
as well, can't we? The tail's a bit

different. But yeah, definitely no
spikes on the underside. No pelvic

And these freshwater sticklebacks look a
little bit more like these guys in the

tank here.

So a mutation has accumulated in the
spike -making genes.

And why would this happen in fresh
water? Well, it might not be a

because in fresh water, if you're a
fish, you probably don't need the

from predators that you would need in a
marine environment.

And in fact, it might be an advantage
not to make your spike anymore. Why

energy making this defensive spike if
you don't need one?

Now, scientists have worked out which
gene has mutated in the fresh water.

compared with in the marine
sticklebacks.

And in the freshwater fish, it turns out
that this spike -making gene is

switched off in these cells that would
normally make the spikes.

So the freshwater sticklebacks don't
make these spikes anymore.

So the gene is switched off.

And in fact, these scientists have gone
a step further, and they've shown that

you can even put the spike -making gene
back into these cells on the underside

of the lake fish, and they grow a spike
again. So you can switch the fish from

the freshwater variety to the marine
variety by switching the gene back on

in these cells that would make the
spike.

And these same scientists have found out
that it's a deletion of DNA that causes

the change in these lake -bound
sticklebacks. So just a few bases get

ta -da! The gene fails to switch on.

And there's no spike.

This is the molecular mechanism of
change, or one of the molecular

change, what Darwin never knew.

And it's an example of a simple change
in switching a gene on or off that can

result in a change in part of the fish's
anatomy, which has led to an organism

with different features.

How does this ever change one species
into another species altogether?

To help us investigate this, I want to
introduce you to an evolutionary

developmental biologist.

Ladies and gentlemen, please welcome
Peter Holland.

Peter! Peter!

See, you've got a friend with you.

Yes, this is Rue the Cockerel. Rue the
Cockerel. Very nice.

And I think there's something else
following you on here.

Goodness me!

Isn't that beautiful?

What's his name?

This is Pebbles the Goose. Pebbles the
Goose. Now, I can see that what we're

going to do now is discuss the
differences between chickens and geese.

Yes, yes.

Well, there's quite a lot of
differences, actually, as you can see. I

to point a few of them out, the beak is
a very different shape, the feet are

very different.

But I thought what we would really
discuss is... A very interesting

which is the length of the neck. If you
compare this in the goose here to this

very short neck. Yeah, a chicken's got
hardly any neck at all. So maybe the

way to see those differences would be to
look at some skeletons.

Have we got some geese and some chicken
skeletons?

We have, indeed.

I can conjure up anything in this
lecture theatre. It's amazing, isn't it?

you been relieved of your chicken? Yes,
I have. Right.

So here we are with a goose and a
chicken skeleton. So we have a goose and

chicken skeleton, and we can see the
differences really well here.

Of course, thinking about the neck,
there are two possible different ways we

could make a longer neck.

These segments, these bones, these
vertebrae in the neck could be larger,

could have more of them. And you can see
here there are many more of the

vertebrae in the neck of the goose.

There are 17 here in the neck of the
goose, and far fewer in the chicken over

here. So the number has changed.

Gosh, and is this all going to be down
to changes in particular genes as well?

Yes, there's a set of genes which we
know have been very involved in the

evolution of this difference. It's a
group of genes called Hox genes, my

favourite genes.

Now, what Hox genes do is they tell
cells in the embryo where they are.

Cells need to know their position so
they can do the right things.

And then what the Hox genes also do is
switch on, they control other genes so

that the cells make the appropriate
structures.

So they're very important genes.

So, for example, in the embryos of these
birds, we would have Hox genes saying,

oh, you're in the neck region of the
animal, so don't.

You don't grow any ribs, for example,
but further back, a different set of hox

genes would be saying, no, here you
should be growing ribs because you're in

thorax region of the embryo. But these
two species have the same hox genes.

It's just the expression of them, which
cells switch on which genes, which is

different. So the hox genes are switched
on and off differently in the geese

compared with in the chicken. So the hox
genes have different expression

patterns. Absolutely. Perhaps I can...

Demonstrate that.

Oh, no, not more paint.

Using more paint.

You're not going to paint the skeleton,
surely?

Is that all right? No, no, no, no, no.
These are from the Oxford University

Museum of Natural History. But we do
have some models that we may be able to

you paint.

Okay. Let's give this a try.

Ah, here they are.

Oh, very fine. They look as well.

So we have a goose and we have a
chicken.

And I'm going to stand right out of the
way at this point.

So this paint is going to represent a
particular Hox gene, which is going to

tell the cells that they're in the part
of the body which is going to be the

thoracic region. So it's to sort of
build the ribs.

So in this chicken here, this gene would
be expressed sort of in that region.

But this will be happening in the
embryo, when all the segments of the

still look exactly the same.

So that gene is being switched on and
telling those cells where they are,

make the appropriate structures.

Lots of rib there. But in the embryo of
the goose over here, the expression of

this same gene will start further back.

So it will start here, down there.

And again, this is happening in the
embryo before those segments start to

different from each other. So you can
see here how the expression of the genes

in the embryo feeds all the way through
to the structure of the animal.

And so we're ending up with...

a lot more neck here, and the ribs are
further back, and we're ending up with

less neck there in the chicken, and the
ribs are further forward. Yeah,

absolutely.

So chickens have more rib and less neck,
and it's the other way around in the

geese. Yeah. Right. So evolution has
changed the way the animal looks by

altering Hox gene expression.

That's a pretty amazing mechanism.

How far could we go with this?

Does it apply to other animals?

For example...

What about these animals?

Hello, Lindsay.

You've brought some other little
creatures to share. Would anyone like to

snake?

Would you like to come down?

Thank you very much.

I'm sure some others of you can have a
go later. If you'd just like to stand

here. What's your name?

Robert.

Right, round your neck, Robert.

Just to be light.

Oh, aren't they lovely and warm?

Hang on, we're having a bit of a...

cuddle here don't worry it won't
strangle you not not tonight anyway no

it feel cold i thought they were quite
warm they're very silky aren't they

they're not slimy at all absolutely
beautiful and what about this one here

snake yeah you didn't have a color with
a rat did you uh no good you're all

right then you're safe might sniffed a
bit of rat around he's rather splendid

isn't he So what's the deal with these?
Are they all rib or are they all neck?

Well, obviously you can see that all the
way down the body it looks very

similar. But you can feel really that
the skeleton, this is ribs, pretty much

all the way down the body. Very tough,
isn't it? It's grabbing me quite tightly

now. So maybe we should have a look at a
skeleton. Yeah, let's look at the

actual skeleton of the snake.

Ah, look at that.

Fantastic.

Isn't that the most beautiful skeleton
you've ever seen? Yeah, you can really

feel the ribs now.

All the way, there's a very, very small
region of neck just behind the skull.

But apart from that, it's ribs all the
way down the length of the body there.

And again, that can be traced right back
to the embryo when those segments are

making their decisions about what
they're going to develop into.

So these hot shoes are really important,
aren't they?

Yeah, they're extremely important.

So I think we'd better maybe say goodbye
to the snakes.

And maybe think about one other animal.
Okay.

So what about us?

How do we do in the neck versus ribs
department?

Let's have a look. This is Jackie, the
Royal Institution resident skeleton.

She's a bit delicate, but I think maybe
we should turn her around to have a

better look at her vertebrae. Well, of
course, we're mammals, and mammals

show... So this regionalisation of the
skeleton extremely well. So you can see

the neck region here. There's just seven
segments, a very short neck, seven

segments in the neck. And then we have
the thoracic region here with the ribs.

Then the lumbar region, which is the
lower back. And each region of the body

specialised. Those segments have been
specialised in different ways. So we've

got relatively short necks. So more
chicken than goose? Possibly more

than goose, yeah. And is that hox genes
as well in us?

Yes, it almost certainly is, Hox genes.
But there's a lot we don't know.

We don't really know how evolution, what
sort of mutations are happening in

evolution to change the boundaries of
Hox gene expression, which we see in

different species.

So it sounds like there's a long way to
go in this kind of research.

So I guess you'd better go and get on
with it then. Okay. Thank you so much,

Peter. Thank you.

So changes in gene expression patterns
can explain a lot then, can't they?

Gene switches are not just at the very
heart of development, making cells

different from one another, they're also
at the very heart of evolution, making

organisms different from one another.

Suddenly it all makes sense that we
share so many genes with animals that

completely different from us.

And this is the magic of evolution.

Over eons of time, a single species can
give rise to so many.

An ancient fish can evolve to become the
ancestor of all four -limbed animals.

Even us.

Imagine how excited Darwin would have
been if he'd known all this.

Many people wonder what makes humans so
special. What are the special genes that

humans have that set them apart from
other creatures?

The truth is that there are no entire
genes that are completely unique to

humans. No more than there are any genes
completely unique to anything.

We have a few more of one type of gene,
a few less of others, a tweaking

expression pattern here, a small
adjustment in protein function there. We

just a cog in the wheel of life.

Fantastic.

So is that it?

Have we reached the pinnacle?

Evolved as far as we can?

Reached perfection?

Evolution must have stopped.

Really?

Do you think all these processes have
stopped?

Has mutation stopped?

Has natural selection stopped?

Whatever the answers to these questions,
personally, I think we humans are

extraordinarily privileged, even now, to
have evolved a brain advanced enough to

both appreciate and start to understand
the fantastic life all around us.

Ladies and gentlemen, thank you and good
night.

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