Scientists have discovered surprising genetic changes that may explain the extraordinary leap in human intelligence compared to our closest relatives. A new study published in quantitative biology shows that two dramatic “salts” in gene regulation (evolutionary jumps) shape our unique cognitive abilities from language development to social cooperation, although humans share 98.77% of our DNA with chimpanzees.
The study addresses one of the most fundamental questions of science: “What genetic changes make us unique to humans?” Instead of examining the protein-encoding genes themselves, the researchers analyzed regulatory switches that control when and where genes turn on or off. Their findings reveal how specific changes in these regulatory areas trigger significant cognitive abilities that distinguish humans from other primates.
What makes this approach groundbreaking is how it recognizes specific characteristics of humans without any preconceived notion that makes humans special. But how exactly do these regulatory changes create the idea that ultimately builds civilization, forms a symphony and explores the space?
Regulatory regulations behind human intelligence
The research team, led by Xiaomi Li, Ejima Shia and Lei M. Li, developed a mathematical framework to analyze the frequency of regulatory elements – short DNA sequences that help control gene expression – across the genomes of humans, chimpanzees, bones, bonobos and gorillas.
Their analysis shows that although most modes of regulation remain relatively stable among various species, two dramatic shifts have occurred in particular in humans. These “salts” appear in what researchers call the 4/5 and 9/10 “feature levels” – mathematical representation of regulatory patterns.
Salt influence controls several key cognitive functions, including:
- Long-term memory formation and storage
- Development of the cochlea and inner ear (language and music enabled)
- Social behavior (cooperative life is allowed)
- Multiple types of learning (visual, observation and association)
- Explore behavior (to promote human creativity)
- Neuron protection mechanism
- Regulate mood and happiness through serotonin
Mathematical insights into evolutionary jumps
These salts do not gradually accumulate over time, but change drastically, changing the role of multiple genes as networks. The researchers compared this process to physical concepts, such as phase transitions, where small changes in control parameters can trigger dramatic transformations in the system.
What makes this mathematical approach particularly valuable is its ability to reveal evolutionary progressive and salt within the same framework. Although protein sequences usually develop gradually, researchers have found that regulatory networks can gradually change and leap dramatically.
This dual nature helps explain how species that share the vast majority of DNA show such profound differences in cognitive abilities.
Mobile DNA elements: The driving force of change
A key finding of the study points to mobile DNA elements, especially ALU elements and SVA (SINE-R/VNTR/ALU), which are important drivers of these regulating transfer. These elements can insert themselves into new locations in the genome, potentially altering the regulation of nearby genes.
The researchers found that the number of regulatory patterns present on human ALU elements increased significantly in intelligence-related regulatory networks compared to chimpanzees and bob bones. For example, when comparing humans with chimpanzees, the number of motifs associated with ALU increased by 43.5% at level 4 and 25% at level 9.
In the analysis, there are several genes with human-specific insertion. For example, the BSG gene ranks 45th in the importance of human level 4, but the BSG gene in apes contains human-specific ALU insertions. This gene plays a role in dendrites’ self-avoidance – a critical process of appropriate neural network formation and memory.
From apes to humans: a regulatory revolution
This study provides a new perspective on the long-term problem of human uniqueness. Although the genetic differences between humans and our closest relatives are small, these specific regulatory changes seem to enable the emergence of human intelligence.
The results show that although most evolutionary changes are progressing gradually, regulatory networks sometimes experience dramatic jumps or “salts”, resulting in profound phenotypic changes, as Darwin proposed. The human brain with extraordinary cognitive abilities may be the product of this evolutionary leap.
This calculation method of studying evolution provides a powerful new tool for understanding the evolution of species. By focusing on regulatory networks rather than individual genes, researchers can capture the complex interactions that shape biological systems.
Going forward, this approach can be applied to different characteristics other than comparison and intelligence in other species. It can also inform research on neurodevelopmental disorders by highlighting the importance of regulatory areas in brain development and function. As we continue to explore what makes us human, this study shows that the answer may not lie in the genes we have, but how we regulate them.
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