ROBERT KRULWICH:
When I look at this--
and these are three billion
chemical letters
instructions for a human being--
my eyes glaze over.
( laughs )
KRULWICH: But when scientist
Eric Lander looks at this
he sees stories.
LANDER:
The genome is a storybook
that's been edited
for a couple billion years
and you could take it to bed
like A Thousand and One
Arabian Nights
and read a different story
in the genome every night.
KRULWICH:
This is the story
of one of the greatest
scientific adventures ever
and at the heart of it
is a small, very powerful
molecule, DNA.
For the past ten years
scientists all over the world
have been painstakingly trying
to read the tiny instructions
buried inside our DNA.
And now, finally, the
human genome has been decoded.
MAN: We're at the moment
that scientists wait for.
This is what we wanted to do.
You know, we're now examining
and interpreting
the genetic code.
MAN:
This is...
The ultimate imaginable thing
that one could do scientifically
is to go and look
at our own instruction book
and then try to figure out
what it's telling us.
KRULWICH:
And what it's telling us
is so surprising and so strange
and so unexpected.
50% of the genes in
a banana are in us?
LANDER: How different are you
from a banana?
I feel--
and I feel I can say this
with some authority--
very different
from a banana.
LANDER: You may
feel different...
KRULWICH:
I eat a banana.
All the machinery
for replicating your DNA
all the machinery
for controlling the cell cycle
the cell surface,
for making, uh, nutrients--
all that's the same.
KRULWICH: So, what does
any of this information
have to do with you or me?
Perhaps more than we
could possibly imagine.
Which one of us will get cancer
or arthritis or Alzheimer's?
Will there be cures?
Will parents in the future
be able to determine
their children's
genetic destinies?
LANDER:
We've opened a box here
that has got a huge amount
of valuable information.
It is the key
to understanding disease
and, in the long run,
to curing disease.
But having opened it
we're also going to be
very uncomfortable
with that information
for some time to come.
KRULWICH: Yes, some of the
information you are about to see
will make you
very uncomfortable.
On the other hand, some of it
I think you will find
amazing and hopeful.
I'm Robert Krulwich
and tonight,
we will not only report
the latest discoveries
of the Human Genome Project
you will meet the people
who made
those discoveries possible
and who competed furiously
to be first to be done.
And as you watch our program
on the human genome
we will be raising
a number of issues:
genes and privacy,
genes and corporate profits
genes and the odd similarity
between you and the yeast.
And we'd like to have your
thoughts on all these subjects
so please, if you will,
log on to NOVA's Web site.
It's located at pbs.org.
It'll be there
after the broadcast
so do it after the broadcast,
where you can take a survey.
The results will be
immediately available
and continually updated.
We'll be right back.
KRULWICH:
To begin, let's go back
four and some billion years ago,
to wherever it was
that the first speck
of life appeared on earth--
maybe on the warm surface
of a bubble.
That speck did something
that has gone on
uninterrupted ever since.
It wrote a message--
it was a chemical message--
that it passed to its children
which then passed it
on to its children
and to its children, and so on.
The message has passed
from the very first organism
all the way down through time
to you and me...
like a continuous thread
through all living things.
It's more elaborate now,
of course
but that message, very simply,
is the secret of life.
And here is that message
contained in this stunning
little constellation
of chemicals we call DNA.
You've seen it in this form,
the classic double helix
but since we're going to be
spending a lot of time
talking about DNA, I wondered
what does it look like
when it's raw, you know,
in real life.
So I asked an expert.
I mean...
DNA has a reputation for being
such a mystical, highfalutin
sort of molecule--
all this information,
your future, your heredity.
It's actually goop.
So, this here's DNA.
KRULWICH: Professor Eric Lander
is a geneticist
at MIT's Whitehead Institute.
LANDER: It's very, very long
strands of molecules--
these double helices of DNA--
which, when you get
them all together
just look like
little threads of cotton.
KRULWICH: And these strands were
literally pulled from cells--
blood cells or maybe
skin cells-- of a human being.
LANDER: Whoever contributed this
DNA, you can tell from this
whether or not
they might be at early risk
for Alzheimer's disease.
You can tell whether or not
they might be at early risk
for breast cancer.
And there's probably about
2,000 other things you can tell
that we don't know how to tell
yet, but will be able to tell.
And it's really
incredibly unlikely
that you can tell all that from
this, but that's DNA for you.
That apparently is
the secret of life
just hanging off there
on the tube.
KRULWICH: And already DNA has
told us things that no one--
no one-- had expected.
It turns out
that human beings have
only twice as many genes
as a fruit fly.
Now, how can that be?
We are such complex
and magnificent creatures
and fruit flies--
well, they're fruit flies.
DNA also tells us
that we are more closely related
to worms and to yeast
than most of us
would ever have imagined.
But how do you read
what's inside a molecule?
Well, if it's DNA
if you turn it so you can look
at it from just the right angle
you will see in the middle what
look like steps in a ladder.
Each step is made up
of two chemicals--
cytosine and guanine
or thymine and adenine.
They come always in pairs
called base pairs
either C and G
or T and A for short.
This is, step by step, a code
three billion steps long--
the formula for a human being.
KRULWICH: We're all familiar
with this thing.
This shape is very familiar...
LANDER: Double helix.
KRULWICH: Double helix.
First of all, I'm wondering...
this is my version
of a DNA molecule.
KRULWICH: Is this, by the way,
what it looks like?
LANDER: Well... give or take,
I mean, a cartoon version...
yeah, a little like that
or so, yeah.
KRULWICH:
So there are in every...
almost every cell in your body
if you look deep enough,
you will find this chain here.
LANDER: Oh, yes, stuck in
the nucleus of your cell.
KRULWICH: Now, how
small is this?
In a real DNA molecule
the distance between
the two walls is how wide?
LANDER: Oh, golly...
( whispering )
KRULWICH: Look at this--
he's asking for help.
LANDER: This distance is
about from...
this distance is
about ten angstroms...
KRULWICH:
That's one-billionth of a meter
when it's clumped up
in a very particular way.
LANDER: Well, no, it's curled
up some like that
but it's more than that.
You can't curl it up too much
because these little
negatively charged things
will repel each other,
so you fold it on its...
I'm going to break
your molecule.
KRULWICH: No, don't break my
molecule-- very valuable.
LANDER: You got this, and then
it's folded up like this
and then those are folded up
on top of each other
and so, in fact
if you were to stretch
out all of the DNA...
it would run, oh, I don't know,
thousands and thousands of feet.
KRULWICH: Okay, the main thing
about this
is the ladder--
the steps of this ladder.
If I knew it was A and T
and C and C
and G and G and A...
LANDER: No, no, it's not
G and G, it's G and C.
KRULWICH: Whatever the rules are
of the grammar, yeah.
If I could read each
of the individual ladders
I might find
the picture of what?
LANDER: Well, of your children.
This is what you pass
to your children.