Summary: Despite sharing over 98% of our DNA with chimpanzees, humans possess strikingly advanced cognitive and emotional abilities. A new study reveals that rapid shifts in gene regulation, rather than changes in protein-coding genes, may explain this leap.
Using a novel analytical method, researchers identified two key regulatory “saltations” unique to humans that influence memory, learning, social behavior, and emotional depth. These findings suggest that human intelligence emerged not through gradual mutation, but through sudden rewiring of how genes are turned on and off.
Key Facts:
- Regulatory Shifts: Two sudden changes in gene control distinguish humans from other apes.
- Cognitive Targets: Affected genes relate to memory, emotion, learning, and social behavior.
- New Model: Highlights gene regulation—not just mutations—as key to human evolution.
Source: Higher Education Press
On its 125th anniversary, Science magazine posed 125 unsolved scientific questions, among which “What genetic changes made us uniquely human?” was listed as one of the 25 core problems.
Yet the divergence rate between the alignable genomes of humans and chimpanzees is as little as 1.23%.
Scientists hypothesized that gene regulation might account for their dramatic phenotypic differences.
Recently, Quantitative Biology published a research article entitled “The human intelligence evolved from proximal cis-regulatory saltations” in which the focus shifted from protein sequences to their regulatory regions.
They represented proximal regulatory sequences of genes using the cis-regulatory element frequency (CREF) matrix. The transcriptional regulatory information from humans and extant ape species—such as chimpanzees, bonobos, and gorillas—was transformed into orthogonal modules that could be aligned and compared.
The researchers extracted 10 principal regulatory modules from the whole-genome data and ranked them in descending order of binding energy.
By comparing the CREF modules of four hominid species, they discovered that two regulatory modules underwent saltations: one between the 4th and 5th eigen-levels and another between the 9th and 10th.
The newly regulated gene targets include those associated with long-term memory, cochlea development, learning, exploration behavior, social behavior, and regulation of sleep and happiness.
Without any a priori, the CREF module can largely explain the saltation of human cognition and intelligence, offering a new quantitative paradigm for studying the evolution of gene regulation.
About this genetics, intelligence, and evolutionary neuroscience research news
Author: Rong Xie
Source: Higher Education Press
Contact: Rong Xie – Higher Education Press
Image: The image is credited to Neuroscience News
Original Research: Open access.
“The human intelligence evolved from proximal cis-regulatory saltations” by Xiaojie Li, et al. Quantitative Biology
Abstract
The human intelligence evolved from proximal cis-regulatory saltations
The divergence rate between the alignable genomes of humans and chimpanzees is as little as 1.23%. Their phenotypical difference was hypothesized to be accounted for by gene regulation.
We construct the cis-regulatory element frequency (CREF) matrix to represent the proximal regulatory sequences for each species. Each CREF matrix is further decomposed into dual eigen-modules.
By comparing the CREF modules of four existing hominid species, we examine their quantitative and qualitative changes along evolution. We identified two saltations: one between the 4th and 5th, the other between the 9th and 10th eigen-levels.
The cognition and intelligence unique to humans are thus found from the saltations at the molecular level.
They include long-term memory, cochlea/inner ear morphogenesis that enables the development of human language/music, social behavior that allows us to live together peacefully and to work collaboratively, and visual/observational/associative learning.
Moreover, we found exploratory behavior crucial for humans’ creativity, the GABA-B receptor activation that protects our neurons, and serotonin biosynthesis/signaling that regulates our happiness.
We observed a remarkable increase in the number of motifs present on Alu elements on the 4th/9th motif-eigenvectors.
The cognition and intelligence unique to humans can, by and large, be identified using only the CREF profiles without any a prior.
Although gradual evolution might be the only mode in the mutations of protein sequences, the evolution of gene regulation has both gradual and saltational modes, which could be explained by the framework of CREF eigen-modules.
