Stargazers aid revolutionary DNA analysis

A team of British stargazers has shown biologists a new way to analyse DNA that could revolutionise genetic research and ultimately medical diagnostics.

An advance developed to study light from distant galaxies is helping scientists to overcome a technical stumbling block that has held back gene-chip research.

Biologists Pat Heslop-Harrison and Trude Schwarzacher and astronomers George Fraser and Andrew Holland, all of them working at Leicester University, have patented the innovation and hope that laboratories around the world will use it. But the work also raises the prospect of hospital-based gene-chip devices capable of making accurate and rapid diagnoses of diseases from a single drop of blood.

Gene chips are research tools that reveal levels of genetic activity. Each chip is covered with tiny spots of DNA from thousands of genes. When a sample is poured on to it, matching genetic sequences bind together.

Fluorescent tags are used to reveal where this has happened and, hence, which genes are active.

If scientists want to compare samples, they have to test them at the same time on the same chip. To tell them apart, each one is given a different coloured tag.

But the limitations of conventional colour-detection technology make it difficult to quantify results and restricts researchers to just two samples with an acceptable level of accuracy.

Professor Heslop-Harrison found the solution to this problem in technology developed at the European Space Agency's laboratories in Holland.

This uses a property of supercooled helium to analyse the light from faint galaxies in the early universe. It turns out that the device, called a superconducting tunnel junction camera, or S-cam, can also be used to read the faint fluorescent colour signals from gene chips.

Professor Heslop-Harrison said this had enabled scientists to compare four biological samples, with the potential to obtain accurate data from seven or more.

Pilot projects are under way to look into the role of genes in the generation of sperm cells and to explore the genetic diversity of modern breeds of cattle.