Nice example of how nuanced science gets hilariously altered in the media

brainby Patrick Hoesly

Newly evolved gene may have changed humans’ brains
[Via Ars Technica]

The completion of human and primate genome sequences (including some close, extinct relatives) reveals a great deal about the evolutionary innovations behind modern humans. All indications are a large collection of relatively subtle genetic changes added up to considerable differences in our brains and anatomy.

So, it was a bit shocking to see a headline claiming a single gene separated us from our fellow apes. The article behind the headline turned out to be wrong, of course. But there was an additional research paper behind that article. The story this told turned out to be rather interesting, even after the hype was stripped away.

The second paper was the product of a research group studying the evolution of human micro RNAs. These are short pieces of RNA that form a “hairpin” structure: two stretches of complementary sequence that can base pair to form a double helix, separated by a short loop that lets the RNA fold back on itself.

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Headline – Scientists Reveal Single Gene Is the Difference Between Humans and Apes” Wow, only a single gene is all it took. Too bad this is pretty much wrong, pretty much not what the researchers said and pretty much just a lazy title to drive clicks.

One reason I love Ars Technics is that they provide useful context regarding scientific research. Here is how another media outlet described the same work in an article  (my bold)”

What makes us human? Some say that it is the development of language, though others argue that animals have language as well. Some say that it is our ability to use tools, though many animals are able to use rocks and other objects as primitive tools. Some say that it is our ability to see death coming.

Now, researchers believe that they have found the definitive difference between humans and other primates, and they think that the difference all comes down to a single gene.

No, as the Ars Technics article details, the paper does not reveal that a single gene is the definitive difference between humans and apes. The paper’s title — Evolution of the human-specific microRNA miR-941 — provides no indication of such a momentous discovery because they did not. Here is how they conclude their paper describing the gene miR-941:

Taken together, the unusual features of miR-941 evolution, as well as its potential association with functions linked to human longevity and cognition, suggest roles of miR-941 in the evolution of human-specific phenotypes. More generally, miR-941 evolution provides an example for rapid emergence of a novel post-transcriptional regulator, thus allowing for a rare opportunity to study consequences of this process on evolution of a regulatory network.

Nothing about a single gene responsible for our becoming humans.

Another example of lack of nuance: the use of the word gene in the headline. Most people think a gene is a segment of DNA that it translated into a protein necessary for life. But the paper  does not describe what most people think of as a gene.

It describes a micro RNA (miR-941a small piece of RNA that controls the expression of many other genes. In recent years, miRNAs have bee found to be very important in the regulation of genes and small changes in miRNAs can have large effects on the developmental expression of specific proteins.

The media article never makes this distinction, calling it a gene – which by definition it is – but not demonstrating its difference from what people expect.

And, as the paper mentions, while miR-941 emerged about the same time as we split from chimps, “Emergence of miR-941 was accompanied by accelerated loss of miR-941-binding sites, presumably to escape regulation.”

So, it acted to decouple gene expression control. Loss of binding sites means it no longer directly inhibited gene expression. Its existence seems to have driven mutations to make its purpose unnecessary. That is certainly a different take on a gene.

Finally, the media article again uses the term “junk DNA” which no real researcher ever believed or uses. We talk about non-coding DNA — such a miRNAs.

miRNAs are one of the great new discoveries of the last decade, proving an important new regulatory underpinning to protein production. But you would not know that if you only read the popular media’s descriptions.

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