The genetic make-up of the mouse has been published for the first time in a scientific journal.

The mouse "book of life" reveals that humans and mice share at least 80% of their genes, with only 300 unique to either organism.

We share 99% of our genes with mice, and we even have the genes that could make a tail

Dr Jane Rogers, Wellcome Trust Sanger Institute

About 1,200 new human genes have been discovered while mining the mouse genome.

Many are involved in cancer and other human diseases and will help the search for new medical treatments.

The mouse data have been produced by a number of US and UK institutions, funded by the National Institutes of Health in America and the Wellcome Trust in Britain.

A private US company has already read the mouse genome but its research is not freely available to scientists - they must pay for access.

In contrast, the work done by the international consortium has been posted on the net and is available to all.

Mouse 'phrasebook'

The public draft of the mouse genetic code - published in Nature - covers about 95% of the genome.

It shows that about 80% of genes in mice and men are like for like.

But if one considers just the different classes of genes - mice have more genes involved in reproduction and smell, for example - then the similarity rises to 99%.

Dr Jane Rogers: "We have deciphered the mouse 'book of life'" (Image by Wellcome Trust)

A fifth of the mouse genome was generated at the Sanger Institute near Cambridge, UK.

"The entire biomedical research community can for the first time fully use this resource to tackle human diseases," said Dr Jane Rogers, head of sequencing.

"They now have powerful tools that will serve them for many decades to come.

"We share 99% of our genes with mice, and we even have the genes that could make a tail."

Human diseases

The information will prove crucial to researchers investigating the human genome, the complete set of biochemical instructions used by cells to build and maintain our bodies.

The mouse genome is published in Nature

The draft of the human genetic blueprint was published in 2001, and is expected to be completed next year. The mouse genome should be finished in 2005.

Comparing the two genomes will help scientists understand how our cells work and why we get ill when one or more of our genes malfunction.

"We have learnt a huge amount about human medical problems by studying mouse genetics," said Professor Robert Winston, director of NHS research and development at Imperial College, Hammersmith Hospital, in London.

"This new landmark announcement is of immense importance and will undoubtedly further our understanding of the molecular basis for human diseases and the treatment of the widest range of human disorders."

Knock-out experiments

Scientists can work out what human genes do by "knocking out" similar looking genes in mice and studying the results.

Researchers can also trace the malfunctioning genes responsible for disease by examining sick mice that display symptoms apparently similar to human conditions.

Professor Allan Bradley, director of the Wellcome Trust Sanger Institute, said the work underlined the importance of animal research in tackling human diseases like diabetes.

He told BBC News Online: "By doing a few experiments in a mouse you can get information on a disease that's going to impact on the lives of hundreds of millions of people."

The mouse genome is bundled into 20 chromosome pairs and the latest analysis suggests that it is about 2.5 billion base pairs, or "letters", in size.

This makes it slightly shorter than the human genome, which has about 2.9 billion base pairs spread out over 23 pairs of chromosomes.

The analysis also suggests the rodent has about 30,000 genes, a figure broadly similar to humans.