Fine-scale analysis of the human brain yields insight into its distinctive composition
Scientists at the Allen Institute for Brain Science have identified similarities and differences among regions of the human brain, among the brains of human individuals, and between humans and mice by analyzing the expression of approximately 1,000 genes in the brain. The study, published online today in the journal Cell, sheds light on the human brain in general and also serves as an introduction to what the associated publicly available dataset can offer the scientific community.
This study reveals a high degree of similarity among human individuals. Only 5% of the nearly 1,000 genes surveyed in three particular regions show differences in expression between humans. In addition, comparison of this dataset to data in the Allen Mouse Brain Atlas indicates great consistency between humans and mice, as the human visual cortex appears to share 79% of its gene expression with that of the mouse.
The dataset, which is publicly available online via the Allen Brain Atlas data portal as part of the Allen Human Brain Atlas, holds promise for spurring further discoveries across the research community. Specifically, it contains detailed, cellular-level in situ hybridization gene expression data for about 1,000 genes, selected for their involvement in disease or neural function, in two distinct cortical areas of several disease-free adult human brains, both male and female.
Genes analyzed in this study fall into three categories: genes that serve as indicators of cell types found in the cortex, genes that are related to particular neural functions or diseases of the central nervous system, and genes that hold value for understanding the neural evolution of different species.
The analysis published today reveals high consistency of gene expression among different regions of the human cortexthe outer rind of the mammalian brain responsible for sophisticated information processingspecifically the temporal and visual cortices. The vast majority of genes expressed in these areas, 84%, demonstrate consistent expression patterns between cortical areas. This finding supports the hypothesis that there are common principles of organization and function that apply throughout the cortex, and therefore studying one area in great detailthe visual cortex, for examplemay hold promise for uncovering fundamentals about how the whole brain works. The study also illustrates widespread conservation of gene expression among human individuals. The study reports that of the genes analyzed, only 46 (5%) showed variation in expression among individual, disease-free human brains in the cortical areas examined.
Distinctions among species
Several findings in the study point to differences and similarities between humans and mice. As the mouse is the most common model for the study of human brain function and diseases, it is crucial to understand how well it represents the human system and where its accuracy may be limited. Overall, the results of this study indicate good conservation of gene expression between the two species. While the majority of gene expression is similar, the authors of the study report some striking differences.
The findings reveal distinct molecular markers specific to each species. Tracing those genes attributable to particular cell typesthe building blocks of brain circuitsthe study authors point to a unique molecular signature for each cortical cell type. These molecular signatures may reflect and contribute to species-specific functions.
According to the study, only 21% of gene expression in the visual cortex exhibited differences between human and mouse, but the nature of those differences may reveal more about what makes us uniquely human. While very little variation among genes in the disease and evolution categories was observed, substantial variation was reported among genes in the cell types category, with a marked number of those genes known to be involved in cell-to-cell communication. These data suggest that intercellular communication may be a key link to unique brain function in humans.
Advancing the field
To date, other studies examining human gene expression have employed either a segmented region of the brain or a select set of genes without specific anatomic information. This human brain dataset as well as the Allen Mouse Brain Atlas and the hundreds of studies published using its data demonstrate that adding high-resolution, cellular-level spatial information to gene expression profiling studies allows scientists to learn a great deal more about how genes contribute to cell types, neural circuits, and ultimately brain function.
The study published today offers a deep introduction to the kinds of information that can be mined from this dataset and the types of hypotheses that it can be used to test. The entire body of data is incorporated into the Allen Human Brain Atlas and is freely available via the Allen Brain Atlas data portal at www.brain-map.org.
More information: Zeng et al., Large-Scale Cellular-Resolution Gene Profiling in Human Neocortex Reveals Species-Specific Molecular Signatures. Cell (2012) doi: 10.1016/j.cell.2012.02.052
Journal reference: Cell
Provided by Allen Institute for Brain Science
- Allen Institute for Brain Science launches Allen Human Brain Atlas May 24, 2010 | not rated yet | 0
- Gene activity in the brain depends on genetic background Oct 19, 2010 | not rated yet | 0
- Allen Institute for Brain Science announces first comprehensive gene map of the human brain Apr 12, 2011 | not rated yet | 0
- Novel analysis sheds new light on the mechanisms of brain development Aug 01, 2011 | not rated yet | 0
- Allen Institute for Brain Science launches new atlas, adds new data and tools to others Nov 14, 2011 | not rated yet | 0
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
Genetics 16 hours ago | 3 / 5 (2) | 0 |
Can human genes be patented? That was the question posed by Alan J. Snyder, vice president and associate provost for research and graduate studies at Lehigh, and Lee Kaplan, scientific director of cellular and molecular genetics ...
Genetics 23 hours ago | 4 / 5 (1) | 0
Researchers from Queen Mary, University of London have led the largest sequencing study of human disease to date, investigating the genetic basis of six autoimmune diseases.
Genetics May 22, 2013 | 4.5 / 5 (4) | 0 |
University of Minnesota Medical School researchers from the Masonic Cancer Center, University of Minnesota, in partnership with the University's Brain Tumor Program, have developed a new mouse model of malignant peripheral ...
Genetics May 20, 2013 | 5 / 5 (1) | 0 |
Northwestern University scientists have shown a gene involved in neurodegenerative disease also plays a critical role in the proper function of the circadian clock.
Genetics May 16, 2013 | 3 / 5 (1) | 1 |
37 minutes ago | not rated yet | 0
43 minutes ago | not rated yet | 1
(AP)—Department of Justice lawyers have again asked a federal appeals court in New York to delay lifting age restrictions and prescription requirements on an emergency contraceptive popularly known as the morning-after ...
31 minutes ago | not rated yet | 0
38 minutes ago | not rated yet | 0
22 hours ago | 5 / 5 (3) | 0 |
Ernie Pyle – an iconic war correspondent in World War II – reportedly said "There are no atheists in foxholes." A new joint study between two brothers at Cornell and Virginia Wesleyan found that only ...
22 hours ago | 2.5 / 5 (4) | 2