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http://www.brain-map.org/

Scientists exploring the blasted terrain of nerves that give rise to crippling ailments like Lou Gehrig's disease now have an atlas to guide them.

The Allen Institute for Brain Science in Seattle unveiled the first phase of the world's first genetic atlas of the mouse spine today on the Internet, posting it alongside an atlas of genes in the mouse brain completed two years ago.

Displaying about 20,000 active genes in the brain and spine, the two databases offer researchers their first look at normal gene activity in the spine and brain, displaying genes that are "turned on" — meaning they're actively producing proteins that are the workhorses of healthy brain and spinal tissues.

"This is an undiscovered world," says Allan Jones, the institute's chief science officer. "To see where every one of the genes is turned on is enlightening."

The twin projects focus on mice, but a similar peek into the human brain is scheduled for completion in about four years. Experts say that the mouse atlas is invaluable all by itself, because mice are widely used to study human diseases.

Researchers focus intensively on mice because they can also breed mice with ailments comparable to those of humans. They can also knock out critical mouse genes and study how the loss of those genes affects health or contributes to disease. An estimated 90% of mouse genes have a counterpart in humans.

Until now, they haven't had a road map of genetic activity in healthy mice to refer to. By mapping active genes, researchers can study their firing patterns, providing clues to their function.

"This is a big deal for scientists," says Gregory Cox, of the Jackson Laboratory in Bar Harbor, Maine. "It's a working tool that will give us the baseline information that we need to know about what genes are important in cells in the spinal cord."

That's because the human genome isn't simply a static alphabet of chemicals that are passed on from one generation to the next. DNA's double helix is constantly in flux. It's dividing to produce new cells, fixing bits of DNA damaged during replication and serving as a template for proteins that maintain and support life.

Genes that are active, or turned on, are playing critical roles in the cells and tissues responsible for sensation, movement, tissue repair and other biological activities. When the system breaks down, and people develop Lou Gehrig's disease, also known as amyotropic lateral sclerosis, Parkinson's disease, Alzheimer's, multiple sclerosis or any one of many other neuromuscular diseases, genes are likely involved.

"It's incredibly important," Cox says, "to understand normal (gene firing) patterns in the spinal cord so we know when we're seeing something abnormal. It's sort of like the picture on the puzzle box. If you don't know what the puzzle looks like, it's hard to put it together."