鈥淚鈥橫 A little confused on timing,鈥� said a reporter at the London press
conference to announce the working draft of the human genome. 鈥淵ou鈥檝e mapped 97
per cent of the genome, sequenced 85 per cent and finished 24 per cent. So why
did you choose now to make your announcement?鈥�
This question more than any other highlights the curious nature of this
week鈥檚 announcement. On the face of it, scientists involved in the Human Genome
Project (HGP) proclaimed that they have sequenced an arbitrary amount of the DNA
needed to make a human. What鈥檚 more, we understand only tiny parts of this
sequence鈥攖he fragments that code for a portion of our genes. The rest
remains a mystery.
Yet researchers involved in the project are in no doubt about the magnitude
of what they鈥檝e done. It is 鈥渆ven more important than the wheel鈥�, says Mike
Dexter, director of the Wellcome Trust, which funded most of Britain鈥檚
contribution to the project.
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So just what is the nature of the achievement announced this week?
Though the timing seems strange, the HGP鈥檚 scientists always intended to
release a 鈥渨orking draft鈥� of the genome. This represents a 鈥済olden path鈥�, a
sequence of DNA bases stretching from one end of the genome to the other. Sure,
there are gaps, but their sequence contains an estimated 90 per cent of all
genes and 95 per cent of those that cause disease. For gene hunters, what we
have now is more than enough to be going on with.
So if we don鈥檛 look too closely, we have pretty nearly all the basic
instructions for building a human body, which is an astonishing feat. Like
landing on the Moon, spelling out the genome really is an inspirational human
achievement.
It is also a technological victory. Robots that have arrived in the past two
years use what鈥檚 called capillary electrophoresis to let the HGP identify 12 000
DNA bases a minute. That鈥檚 a twenty-fold increase in just three years. The
staggering impact of these machines is clear when you realise that more than 60
per cent of the bases sequenced so far were identified in the past year
(see Graph in 鈥淭he end of the beginning鈥�).
But can sequencing the genome really be more significant than inventing the
wheel? Dexter argues that: 鈥淭his code is the essence of mankind, and as long as
humans exist, this information is going to be important and will be used.鈥� Which
is a fair point. But the wheel didn鈥檛 upset anyone, as far as we know. So,
perhaps there is a better historical analogy.
In 1601, when the Danish astronomer Tycho Brahe died, he left highly accurate
observations of the heavens. Johannes Kepler used these records to formulate his
laws of planetary motion, which put the Sun firmly at the centre of the Solar
System. In doing this, Kepler stirred up a theological scandal and fomented a
revolution in thought. Together with Galileo, he helped to move humanity鈥檚 view
of itself away from the centre of God鈥檚 Universe, while his mathematical method
changed forever the nature of science. He laid the foundations for Newton,
decades later, to create his clockwork Universe.
We know that, like Brahe鈥檚 arcane records, the human genome will stir up all
manner of problems for society. Questions such as whether people should be able
to patent genes and whether insurance companies should be privy to our genetic
quirks have already been posed
(see New 杏吧原创, 20 May, p 15).
Worries abound over the creation of an underclass of people who have the 鈥渨rong鈥�
genes.
The genome will also change the way we view ourselves. We tend to see our
genes as the key to who we are. Yet they are only part of the puzzle. You can
bet there are many surprises to come as we learn about how development and
environment influence gene expression.
As Kepler did, so the scientists who use the genome databases are changing
the way science is done. The prime difference will be a huge increase in the
speed at which things happen. Francis Collins, director of the US Human Genome
Research Institute, spent much of the 1980s leading teams in the search for the
cystic fibrosis gene. With the sequence we have today, that task would take just
two weeks, he says. With this degree of acceleration, who knows where we will be
in five years?
Putting aside historical comparisons, one of the unique aspects of the HGP
was its decision to speed up sequencing and publish the results immediately on
the Web. It was a daring decision designed to stop companies cleaning up on gene
patents. It would be wonderful if governments continued to cooperate with
academic researchers for the public good. For all our nascent genetic knowledge,
if we end up with our genes owned by rich corporations and a genetic underclass,
will we really have advanced that much?
