Составлен генетический атлас мозга мыши Allen Brain Atlas В атласе задокументирована деятельность более 21000 генов, имеющих влияние на развитие мышиного мозга, что составляет около 80% всего генетического кода. Т.к. мыши и люди имеют около 90% общих генов, исследование столь же актуально и для понимания наследственных предрасположенностей человеческого поведения.

It is a brain map like no other, has been three years in the making, and promises a revolution in neuroscience: a genomic atlas of the mouse brain has been crafted. For neuroscientists, it is as if the genome project has been melded with Google Earth inside the mind of a mouse.

Unveiled in its full glory today, the Allen Brain Atlas contains 85 million images, and enough data to fill 20,000 iPods. The atlas documents the activity of more than 21,000 genes across the entire mouse brain in such fine detail that it is possible pick out individual cells. Already, the atlas has revealed that the mammalian brain contains “hidden” structures, defined by common patterns of gene activity.

“It is a profound enabling tool that is going to dramatically facilitate and accelerate research,” says Marc Tessier-Lavigne, senior vice-president of the biotech firm Genentech in South San Francisco, US, who is also involved with the company that created the atlas. “By having all of the information collated in one place, you can do all of the searching that would not otherwise be possible.”

Ed Lein and colleagues at the Allen Institute for Brain Science in Seattle, US, created the atlas using a technique called "in situ hybridisation". This involves bathing thin slices of brain tissue in chemically labelled RNA probes that bind to sequences, called messenger RNA, produced by individual genes.

The process had to be repeated for each gene, and for slices of tissue taken from different parts of the brain, to build a 3D map of gene activity that can be navigated using software available on the web.

Family snapshot

To standardise the results, the researchers used inbred male mice from a strain commonly used in brain research, which were all sacrificed at exactly the same age and time of day. “It’s a snapshot,” says neuroscientist Kelly Overly, who worked on the project.

While factors such as age, sex and daily cycles of biological activity are known to affect gene expression, the researchers are confident that many of the patterns of gene activity they have discovered are common features of the mammalian brain.

The map has already revealed that at least 80% of the genes studied are active in the brain – more than had been predicted. Some are “housekeeping” genes, expressed across most of the brain, but most seem to be active in only subsets of cells.

By studying patterns of activity for these genes, the team has identified structures that are invisible to conventional neuroanatomical methods, and more revelations are expected as neuroscientists get to grips with the atlas.

You can query the Brain Atlas and download the Brain Explorer software at www.brain-map.org.

Journal reference: Nature (DOI: 10.1038/nature05453)