News Release

Special report: Personal genomics

Reports and Proceedings

New Scientist

GENOME sequencing is about to get personal. For more than a decade, thousands of researchers around the world have spent about $3 billion to complete the human genome project. It's not finished yet, but even when it is, we still will not have the genome of a single person: the official consensus sequence is based on DNA from 10 different people.

This is not good enough for some researchers. Their goal is to get very personal indeed. "We are proposing to give people their own sequence if they'll have it," says genomicist George Church of Harvard Medical School.

The allure of knowing your own genome is obvious. It holds many of the secrets of your life- and death. It could, for example, reveal if you are likely to develop heart disease or Alzheimer's. Church and other experts think this is no longer a pipe dream. They believe that in less than a decade, people will be able to get their own genomes sequenced for about the price of a laptop or a flat-screen TV. When that happens, the thinking goes, a whole new industry of personal genomics will take off.

The idea is gathering momentum thanks to Craig Venter, the eccentric scientist-entrepreneur who raced government-funded labs to decode the human genome. Earlier this year, he was ousted from Celera, the genome company he founded. But he has bounced back with a plan for a massive non-profit genome sequencing centre in Maryland. And in a widely publicised bid to attract funding for the centre, Venter says he wants philanthropists to donate a few hundred thousand dollars each. In exchange, he'll hand them the sequence of their genomes' coding regions- the 2 per cent or so that encompasses all known genes.

For the record, Venter tells New Scientist he is not "taking orders" from people or setting this up as a commercial service, as some reports have stated. Rather, his goal is to collect sequence information from lots of people, to learn more about the link between genetic variation and disease.

But the centre's goal is also to take DNA sequencing to a higher level, turning it into a fast, cheap technology. "As usual, Craig is accelerating the rate," says Church. "What will happen now is that people will take this seriously."

That's no small task, since the technology has advanced more slowly than expected. The standard method involves breaking a genome into short strands and making multiple copies of every short DNA fragment before it can be sequenced. The first generation of automated sequencers read about 5000 base pairs, or "letters", per day. Today's machines, which use an improved version of the same technique, sequence about a million bases a day. It's impressive, but not enough. With these machines it would still take millions of dollars and many weeks to sequence a person's genome, says Church.

Miniaturisation and high-throughput techniques can only do so much. They might reduce costs to $30,000 per genome, Trevor Hawkins of Amersham Biosciences told a conference in Boston last week. "But to get to $1000, it's going to take some new technologies," he said. One approach is to stick known strands of DNA on chips to "fish" for complementary strands in a sample. With information from the human genome project, Perlegen Sciences in California developed DNA microarrays that detect millions of sequences at a time. The company announced in August that it has worked out the genome sequences of 25 people with the arrays. But at $1.5 million a genome, the cost is still prohibitive.

Perhaps the greatest excitement surrounds a series of methods to sequence single DNA molecules- an approach that does away with the need to make lots of copies of short segments. These could let sequences be read with unprecedented speed.

US Genomics in Massachusetts has developed a machine that scans a single DNA molecule 200,000 bases long in milliseconds. For now, it untangles the DNA and scans the molecule by picking out fluorescent tags located every 1000 base pairs or so. But chief executive Eugene Chan says the company expects to be able to read sequences one base at a time in three or four years. "Our goal is to sequence the genome instantaneously," he says.

Other firms, such as Texas-based VisiGen Biotechnologies and British company Solexa of Essex are also trying the single-molecule approach. The consensus is that it will take at least five years before sequencing technology reaches the point where it's fast and cheap enough to make personal genomics feasible. What's more, it also has to be highly accurate.

That's because our genomes are 99.9 per cent identical. It's the 0.1 per cent differences that determine if we're blonde or brunette, if we'll get heart disease or not. So accuracy is likely to be a tricky issue for personal genomics companies: get a single base pair wrong and a client may conclude they are about to die of a hereditary disease.

Assuming the technology gets this far, what will your genome reveal? Researchers may know a fair amount about genes that cause relatively rare diseases, such as cystic fibrosis, but we're still in the dark about mutations that predispose people to more common problems- cancers, heart conditions or mental disorders such as schizophrenia. "We are really just at the beginning of the field," says David Reich of the Whitehead Institute in Cambridge, Massachusetts.

At the moment, giving somebody a CD containing their complete sequence would be as useful as giving them a book in a foreign language, adds Brad Margus of Perlegen. It would be useless without the right software and the knowledge needed to interpret it.

Yet as sequencing becomes affordable, Margus thinks we'll learn how genetic variation and lifestyle affect the risk of disease, as well as other characteristics. "The technology is going to drive the understanding of the meaning of genomic information. It goes hand in hand," says Chan.

Only then will personal genomics companies be able to offer consumers reasons for knowing their genomes beyond sheer curiosity. And by that time the industry will have to convince people that having their whole genome sequenced will be better than paying for single or multiple gene tests, which a whole different set of companies is working on.

Both avenues will have their pros and cons. But one thing could tip the scale in favour of sequencing. By taking your sequence home and analysing it, you might be able to avoid infringing a company's patent, which is already rumoured to be a big worry for the makers of diagnostic chips. Licensing fees are expected to pile up, increasing the price of the chips, since many genes being tested for will be patented.

How ironic, then, if decoding people's genomes is what ultimately sets them free from the widespread privatisation of their genes.

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Written by Sylvia Pagan Westphal, BOSTON

New Scientist issue: 12 October 2002

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