Cut-price genomes draw closer

Advances in genome sequencing technologies are bringing scientists one step closer to a time when it would cost as little as $1000 to read the entire genetic code of a person, two US teams say.

A group based at Harvard Medical School has developed a method using beads and fluorescent dyes, which they say would cost around $2.2 million at present. The researchers, who published their technique in the journal Science, eventually hope to reduce the cost to $1000 (£562), so that it can be used in the routine diagnosis and treatment of cancer and other diseases.

Meanwhile, scientists based at US firm 454 Life Sciences say they have developed a sequencing method that is 100 times faster than current technology. The team, who published their study early online in the journal Nature, say that in the next few years it will be possible to assemble an entire human genome for $10,000 (£5620).

The entire human genome sequence, the first draft of which was published three years ago, cost an estimated $3 billion, with mammalian genome projects today costing between $10-$50 million. Last year, the US National Institutes of Health (NIH) invited proposals to develop new, cheap technologies, aimed at developing a '$1000 genome' by 2014. It also sought to fund interim research to develop a '$100,000 genome', which is thought to be achievable within five years.

The Harvard team, lead by George Church, say their new method could make personalised medicine - the prevention, diagnosis and treatment of diseases tailored to a person's genetic make-up - a reality. Their technique relies on replicating thousands of DNA fragments attached to tiny beads. Four differently-coloured fluorescent dyes then stick to each location in the DNA sequence - one for each of the four chemical 'bases' that make up DNA, known  as A, C, G and T. A microscope, digital camera and computer are then used to collect and analyse the data. The scientists used the method to read the entire genetic code of the gut bacteria E.coli.

The group at 454 Life Sciences has developed a method based on a technique called pyrosequencing, which generates flashes of light every time a DNA base is analysed. The scientists have already used the technology to sequence the genomes of 50 microbes. Company founder Jonathon Rothberg was inspired to develop the technology six years ago, after his newborn son had to stay in a hospital intensive care unit. He found himself wishing that he could just read the boy's genome to find out what was wrong, Nature News reports. 'Much like the personal computer opened up computing to a larger audience, this work will enable the widespread use of sequencing in a number of fields, and ultimately place machines in your doctors office', he predicts.