The brain is one of the most complex structures of organized matter known to science. For the past several years, the Allen Institute (founded by Microsoft pioneer Paul Allen) has been engaged in a mind-boggling project: to create a comprehensive genetic map of the human brain.
Researchers have previously been able to map mouse brains, but human brains are 1,000 times larger and more complex. By understanding the human brain’s structure, circuitry and cellular diversity, scientists can gain a better understanding of how the brain is affected by diseases and drugs.
The Allen Institute is employing a combination of large-scale Agilent microarray profiling, 3D data visualization and computer modeling to create their brain atlas. Scientists used a customized Agilent Whole Human Genome probe set to measure gene expression levels in more than 3,700 dissected samples from six adult human brains. The resulting data set, the largest of its kind, has been made freely available to the scientific community.
The project revealed that 80 percent of genes are turned on in the brain, and successfully mapped the locations of genes associated with specific functions.
The researchers looked in particular at the brain’s transcriptome (the set of messenger RNA molecules), which indicates what genes are being actively expressed at any given time. They found that even among different individuals, there are regions of the brain – particularly the neocortex – that have similar molecular signatures. This suggests that there is a common blueprint for the human brain transcriptome.
(The neocortex, found only in mammal brains, is involved in higher brain functions such as sensory perception, motor commands, spatial reasoning, conscious thought and language. Compared to other species, humans have the largest neocortex relative to overall brain volume.)
Mike Hawrylycz, Ph.D, is senior director of Informatics with the Allen Institute for Brain Science. He recently presented a technical e-seminar on “Computational Approaches to Transcriptome Signatures in the Human Brain.” A replay of Dr. Hawrylycz’s presentation is available here. His slides (in PDF) are available here.
For more information go to:
- Computational Approaches to Transcriptome Signatures in the Human Brain (eSeminar)
- Computational Approaches to Transcriptome Signatures in the Human Brain (PDF)
- Michael Hawrylycz: Creating a 3D brain map to aid research (YouTube)
- Allen Brain Atlas Data Portal
- An anatomically comprehensive atlas of the adult human brain transcriptome
- Canonical genetic signatures of the adult human brain
- Agilent Microarrays