Complete mouse DNA map soon

All living things on Earth have a DNA blueprint

By BBC News Online science editor Dr David Whitehouse

US researchers decoding the mouse genome say they have succeeded in sequencing approximately 1.15 billion base pairs of the animal's DNA.

Like the human genome, the mouse has about three billion letters of code in its "book of life".

Remarkably, however, Celera Genomics only began sequencing the mouse genome on 6 April, 2000. Celera's human genome work is also progressing extremely fast and a company announcement that it has all the human letters in the right order is expected any day.

The mouse shares many genes with humans...

Celera intends to make money by providing subscribers with the ability to compare genomes from various organisms.

Scientists will eventually be able to compare and contrast DNA from the mouse, the fruit fly (Drosophila melanogaster) and humans, as well as other animals such as the dog and chicken. Celera finished mapping Drosophila melanogaster in March and believe as many as 60% of the fly's genes will be found in human beings.

This science, comparative genomics, is expected to open many new areas of research into the way genes work and their role in disease.

Model organism

Sequencing the mouse is important because it is a so-called model organism used extensively for studies of human biology and medicine.

...as does the fruit fly

As with the fly, humans have many genes in common with the mouse and having access to the mouse genome should allow researchers to make discoveries about what makes us similar to, and different from, mice.

"The availability of the mouse genome is crucial to understanding the human genome. Mice can function as translators of the human genome in that changes in their genetic material can teach us how changes in DNA lead to predisposition to disease and responses to medical treatments,'' said Dr Craig Venter, Celera's president.

At the current rate of progress, the mouse genome will be completed before the end of the year. Celera is using the 129/SvJ strain of mouse for sequencing. This is a familiar strain in labs worldwide.

Human milestone soon

In January, Celera announced it had compiled data covering 90% of the human genome. In April, it announced it had completed the sequencing phase of the genome from one human being.

The announcement that the entire human DNA sequence is in order is expected very soon. At about the same time, an international team of publicly funded scientists will announce the same thing.

"It is pretty exciting to be at this stage at last where we can see the whole genome, see exactly what needs to be done and be able to move on to the next stage," said Dr Robert Waterstone, director of the genome sequencing centre at Washington University School of Medicine in St. Louis, one of the leaders of the Human Genome Project.

Once the sequence is in the right order, researchers will attempt to map out the locations of all the genes written in the code. This is a process known an annotation and could take many years.

The genes are the templates used by cells to make the proteins that build and maintain the body.