Human brains “share a consistent genetic blueprint and possess enormous biochemical complexity,” according to a study done by the Allen Institute for Brain Science. Microsoft co-founder Paul Allen financially supports that resarch organization.
The study’s findings are the result of a ” deep and large-scale analysis” of the data set publicly available in the Allen Human Brain Atlas.
The results, reported in the latest issue of the journal Nature, are based on an analysis of the Allen Human Brain Atlas, “specifically the detailed all-genes, all-structures survey of genes at work throughout the human brain,” the institute said in a press release last week.
“This data set profiles 400 to 500 distinct brain areas per hemisphere using microarray technology and comprises more than 100 million gene expression measurements covering three individual human brains to date,” the release said.
According to the findings, “84 percent of all genes are expressed somewhere in the human brain and in patterns that are substantially similar from one brain to the next,” according to the release, which was widely reported by the media.
“This study demonstrates the value of a global analysis of gene expression throughout the entire brain and has implications for understanding brain function, development, evolution and disease,” Ed Lein, associate investigator at the Allen Institute and co-lead author on the paper, said in a statement. “These results only scratch the surface of what can be learned from this immense data set. We look forward to seeing what others will discover.”
Here is the big takeaway from the study: “Despite the myriad personalities and cognitive talents seen across the human population, our brains are more similar to one another than different. Individual human brains share the same basic molecular blueprint” and a “shared architecture,” according to the press release.
The study’s other findings were:
- Neighboring regions of the brain’s cortex — the wrinkly outer rind — are more biochemically similar to one another than to more distant brain regions, which has implications for understanding the development of the human brain, both during the lifespan and throughout evolution.
- The right and left hemispheres show no significant differences in molecular architecture. This suggests that functions such as language, which are generally handled by one side of the brain, likely result from more subtle differences between hemispheres or structural variation in size or circuitry, but not from a deeper molecular basis.
- Despite controlling a diversity of functions, ranging from visual perception to planning and problem-solving, the cortex is highly homogeneous relative to other brain regions. This suggests that the same basic functional elements are used throughout the cortex and that understanding how one area works in detail will uncover fundamentals that apply to the other areas, as well.
In addition to those findings, the study provided information on the inner workings of the brain at the molecular level – “the level at which diseases unfold and therapeutic drugs take action,” the release said.
- 84 percent of all genes are expressed, or turned on, somewhere in the human brain.
- Many previously uncharacterized genes are turned on in specific brain regions and localize with known functional groups of genes, suggesting they play roles in particular brain functions.
- Synapse-associated genes — those related to cell-to-cell communication machinery in the brain — are deployed in complex combinations throughout the brain, revealing a great diversity of synapse types and remarkable regional variation that likely underlies functional distinctions between brain regions.
“The tremendous variety of synapses we see in the human brain is quite striking,” Seth Grant, professor of molecular neuroscience at the University of Edinburgh and collaborating author on the study, said in a statement. “Mutations in synaptic genes are associated with numerous brain-related disorders, and thus understanding synapse diversity and organization in the brain is a key step toward understanding these diseases and developing specific and effective therapeutics to treat them.”
The Allen Human Brain Atlas is an open, public online resource that details genes at work throughout the human brain. Data incorporated into the Atlas include magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), as well as histology and gene expression data derived from both microarray and in situ hybridization (ISH) approaches.
The Allen Human Brain Atlas is used in small and large-scale applications to examine diseases and disorders, such as epilepsy, Parkinson’s disease, autism, schizophrenia, and Alzheimer’s disease—as well as to understand how the healthy brain works.
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