NOV 26, 2017 3:49 PM PST

The Molecular Signature of the Human Brain

WRITTEN BY: Carmen Leitch

As a species, humans have close living relatives in other primates. Researchers have been looking at the things that make us distinct from them. One conspicuous part of the body that has differences is the brain. Although the molecular signatures of human brain regions have many similarities to those in primates, some areas are uniquely human in their abilities and evolution, researchers have found. An enormous study of human, chimpanzee, and monkey tissue reported in Science has shown that the human brain is larger than the ancestral primate brain, and has gained distinct biological properties.

Reconstructed fiber tracts that run through the mid-sagittal plane of the human brain / Credit: Wikimedia Commons/Thomas Schultz

"Our brains are three times larger, have many more cells and therefore more processing power than chimpanzee or monkey," said the co-lead author of the study Andre M.M. Sousa, a postdoctoral researcher in the lab of neuroscientist Nenad Sestan. "Yet there are also distinct small differences between the species in how individual cells function and form connections."

While there were differences in brain size, the scientists were surprised to find similarities in gene expression in sixteen different parts of the brain in humans and apes. The area with the most similarity is the striatum, a region linked to movement. Even the prefrontal cortex, where higher order thought takes place, had commonalities.

There were also striking differences within even ancient regions of the brain like the cerebellum. One gene active only in the cerebellums of humans, ZP2, was revealed in the research. That was a surprise to the researchers, who said that gene has been associated with sperm selection by ova.

"We have no idea what it is doing there," said Ying Zhu, a postdoctoral researcher in the Sestan lab and co-lead author of the paper.

Two genes that are linked to the synthesis of dopamine were found by the investigators to be unregulated in humans; tyrosine hydroxylase (TH) and dopa (3,4-dihydroxyphenylalanine) decarboxylase (DDC). Dopamine has a known role in aspects of behavior and thought, like reasoning, working memory, and general intelligence. It was also confirmed that TH is expressed at a high level in human neocortex and striatum; it is not found in the chimpanzee neocortex. "The neocortical expression of this gene was most likely lost in a common ancestor and reappeared in the human lineage," noted Sousa.

Another gene found by the researchers at higher levels, this time in the human prefrontal cortex, was MET. That gene has been linked to autism spectrum disorder.

The work was performed by analyzing tissue samples harvested from five macaques, five chimpanzees, and six humans. Transcriptional profiles were generated for a total of 247 tissue samples, covering several regions of the brain including the amygdala, striatum, mediodorsal nucleus of the thalamus, hippocampus, cerebellar cortex, and neocortex.

The video above is from the University of California; it discusses the human brain and how it evolved.

Sources: AAAS/Eurekalert!, Yale, Science

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 08, 2021
Microbiology
Manganese Could be an Achilles' Heel for Some Pneumonia Germs
AUG 08, 2021
Manganese Could be an Achilles' Heel for Some Pneumonia Germs
Researchers recently discovered bacteria that fed on the element manganese. Scientists also know that some bacterial pat ...
AUG 17, 2021
Cell & Molecular Biology
Structural Variations in the Cacao Genome Reflect Local Adaptations
AUG 17, 2021
Structural Variations in the Cacao Genome Reflect Local Adaptations
The genome is more than just its sequence; epigenetic features of DNA, like chemical tags that may be attached, or how i ...
AUG 18, 2021
Microbiology
Researchers Learn How a 'Crop-Killing' Bacterium Infects Plant Cells
AUG 18, 2021
Researchers Learn How a 'Crop-Killing' Bacterium Infects Plant Cells
In a world with a growing population and a changing environment, food security is an important issue. Scientists have be ...
AUG 20, 2021
Health & Medicine
Nanotechnology and Management of COVID-19- A Promising Future?
AUG 20, 2021
Nanotechnology and Management of COVID-19- A Promising Future?
The rate of viral spread and high mortality demanded a quick response to COVID-19.  As such, pre-existing drugs wer ...
AUG 26, 2021
Coronavirus
Researchers View COVID-19 Progression in a Live Animal Model
AUG 26, 2021
Researchers View COVID-19 Progression in a Live Animal Model
Scientists have used a mouse model to visualize the progression of a SARS-CoV-2 infection as it led to sometimes fatal c ...
SEP 06, 2021
Genetics & Genomics
How a Genetic Mutation Could Lead to Leaky Gut
SEP 06, 2021
How a Genetic Mutation Could Lead to Leaky Gut
In our gut, there is a vast community of microorganisms. It's crucial that they stay there in the gastrointestinal tract ...
Loading Comments...