OCT 12, 2021 9:30 AM PDT

Is It the Junk [DNA] That Makes Our Brains Human?

WRITTEN BY: Carmen Leitch

Scientists have long sought to understand what makes us human. From the standpoint of DNA sequences, we have a lot in common with our closest evolutionary relative, the chimpanzee. The regulation of gene expression seems to be one critical aspect of our biology that makes us different from other species. New work has also identified important regions of non-coding DNA, once dismissed as 'junk' because it had no obvious function and was highly repetitive, which seem to play an important role in the function of the human brain.

Image credit: Pixabay

Humans and chimpanzees split from a common ancestor about 5 or 6 million years ago. Our DNA sequence is about 6 billion base pairs long, and about 35 million bases in the sequence are different from chimpanzees. There are also about 5 million places where insertions or deletions have occurred, as well as a few chromosomal rearrangements. Plenty of those changes have happened in parts of the genome that code for protein, which is what most research has focused on. About 50 human genes are not found in the chimp genome.

But there are also places in the human genome that have remained there over thousands of years even though they have no obvious function, and are sometimes called 'gene deserts.'

In this study, which was reported in Cell Stem Cell, researchers engineered human and chimpanzee stem cells for growth in culture; these cells were made by reprogramming skin cells taken from adults. The brain stem cells from the two species were compared directly, and the researchers identified a genetic region that was utilized differently in human stem cells compared to chimp stem cells. This change impacted the structure of DNA, and not a protein-coding gene, surprising the researchers.

"This suggests that the basis for the human brain's evolution are genetic mechanisms that are probably a lot more complex than previously thought," since it was assumed that the small potion of our genome that codes for protein, about two percent, held the answers to what was different, said study leader Johan Jakobsson, professor of neuroscience at Lund University.

This work has indicated that the other 98 percent of the human genome may contain the parts that are crucial to the unique features of the human brain. "This is a surprising finding," added Jakobsson.


Sources: Cell Press, Cell Stem Cell

About the Author
BS
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 07, 2022
Cell & Molecular Biology
Vitamin K Revealed as Potent Cell Death Suppressor
AUG 07, 2022
Vitamin K Revealed as Potent Cell Death Suppressor
Researchers have known that vitamin K has antioxidant properties, but the mechanism behind that function remained obscur ...
AUG 08, 2022
Genetics & Genomics
This Weed is a Super Plant, Providing Insight Into Drought Tolerance
AUG 08, 2022
This Weed is a Super Plant, Providing Insight Into Drought Tolerance
You may have seen a 'super plant' growing in between the cracks of sidewalks. Portulaca oleracea is commonly known as pu ...
AUG 20, 2022
Technology
Biofilm can Convert Energy from Evaporation into Electricity
AUG 20, 2022
Biofilm can Convert Energy from Evaporation into Electricity
In a recent study published in Nature Communications, a team of researchers at the University of Massachusetts (UMass) A ...
AUG 15, 2022
Microbiology
Untangling the Links Between Alcohol, Liver Disease & Gut Microbes
AUG 15, 2022
Untangling the Links Between Alcohol, Liver Disease & Gut Microbes
Chronic alcohol use is a serious health problem, and a major contributor to liver disease and mortality. The gut microbi ...
AUG 15, 2022
Drug Discovery & Development
New Drug Candidate Treats Over 300 Drug Resistant Bacteria
AUG 15, 2022
New Drug Candidate Treats Over 300 Drug Resistant Bacteria
Researchers have identified a new molecule that shows promise in inhibiting over 300 drug-resistant bacteria, including ...
SEP 14, 2022
Genetics & Genomics
Neurodegeneration is Linked to Jumping Genes
SEP 14, 2022
Neurodegeneration is Linked to Jumping Genes
Scientists are beginning to reveal the secrets of the long, repetitive sequences in the human genome that were once writ ...
Loading Comments...