Researchers at the University of Iowa have found that rare regulatory sequences in DNA, which strongly influence language abilities, appeared even before the split between modern humans and Neanderthals.
A new study from the United States suggests reexamining one of the fundamental questions in the study of human evolution: when did the biological elements that made complex language possible appear? According to researchers from the University of Iowa, certain regulatory sequences in human DNA, which have an unusual effect on language abilities, appeared even before the evolutionary split between modern humans and Neanderthals. If this conclusion is correct, it means that at least some of the biological "hardware" necessary for language existed much earlier than was commonly thought.
The study, published in the journal Science Advances, focused on a group of regulatory sequences called HAQERs – short for Human Ancestor Quickly Evolved Regions. These are not the genes themselves, but regions of DNA that act like a kind of “power switches” for other genes, that is, regions that regulate how much certain genes will function and with what strength. According to the researchers, these sequences make up less than one-tenth of a percent of the genome, but their influence on human language abilities is about 200 times greater than that of any other genomic region.
The research team, led by Prof. Jacob Michelson, relied, among other things, on a unique database that was built in the 1990s. During those years, researcher Bruce Tomblin documented the language abilities of 350 students in Iowa, and also collected saliva samples from them that were preserved for future sequencing. Now that it was possible to sequence the DNA and combine the genetic data with the language indicators, the researchers could examine which genetic variations were associated with each individual's linguistic ability.
The key finding was that HAQERs are a particularly ancient part of the biological system that supports language. The researchers developed a computational measure called ES-PGS, which divides genetic influences into different evolutionary layers, and used it to analyze about 65 million years of evolution. The analysis showed that these regulatory sequences were also present in Neanderthals, and perhaps even slightly more prominent in them than in modern humans. This does not mean that Neanderthals spoke exactly like us, but that at least some of the genetic infrastructure that allowed for complex language appeared even before the separation between the two branches.
The brain is the hardware, language is the software.
The researchers use a simple analogy: if the brain is the “hardware,” then language is the “software.” In other words, HAQERs are not language itself, but genetic components that help build a brain capable of supporting it. Against this background, the team’s cautious conclusion is that early humans and Neanderthals shared at least some of the basic biological capabilities necessary for complex communication. They say that when you combine this finding with archaeological evidence that Neanderthals had complex culture, social organization, and behavior, it strengthens the impression that some complex communication could have existed among them as well.
However, the study also explains why this genetic region did not continue to “upgrade” indefinitely during human evolution. According to the researchers, this is where a mechanism of balancing selection comes into play. HAQERs encourage fetal brain development in a way that also enlarges the brain and skull. However, before modern medicine, there was a clear biological limit to fetal head size: a head that was too large could make birth very dangerous for both mother and baby. Therefore, the researchers speculate that evolution reached a kind of “ceiling” in this pathway relatively early on – enough brain to enable the basics of language, but not too much in a way that would increase the risk of birth. Other traits related to cognition could have continued to develop in different genetic pathways, which are not directly dependent on fetal brain enlargement.
The distinction between genetics and environment
One interesting aspect of the study is the distinction between genetics and environment. Michelson and his colleagues emphasize that even if certain sequences make an important contribution to language ability, the linguistic environment in which a child grows up still plays a central role. So the next step in the study will be to examine the families of the original participants, who have now started families of their own, to better separate direct genetic influence from what the researchers call “genetic nurturing” – a situation in which parents’ genetics also affect the environment they create for their children.
The research could have a broad impact on the long-standing debate over what exactly makes the Homo sapiens Compared to its ancient relatives. Rather than thinking of language as a feature that appeared all at once and only in modern humans, the study suggests a more gradual picture: Some of the biological elements were ancient, and perhaps shared with Neanderthals as well, while the final combination of biology, culture, learning, and environment gave rise to modern humans' linguistic ability in all its richness. This is not yet a "smoking gun" that proves how Neanderthals spoke, but it is certainly a finding that broadens the scope of the discussion, and reminds us of how the boundary between us and our ancient relatives may be more complex than the simple image of "they didn't speak, we did."
More of the topic in Hayadan:
One response
As the article presents it, it is at best ridiculous.
Two examples: The article discusses the aspect of brain and head size, which may endanger the mother-to-be.
The gorilla, whose brain is less than half that of a human, is much larger than a human. In other words, since the hominin brain has been growing gradually over millions of years, there was no fundamental obstacle to further growth in the female.
The second example, the brain, perhaps under mental constraint, can be considered hardware, but language cannot be considered software at all. Language is a person's ability to perform actions, just as he has the ability to perform many actions that are not at all dependent on language, such as walking, eating, working in many and very diverse fields. All of these actions are not at all self-evident, but are acquired in learning processes throughout a person's life.