At Quanta, science writer Annie Melchor writes about the remarkable way that our cells’ RNA — ribonucleic acid — operates as a sort of text messaging system between cells. It does not just convert DNA into protein.
How could RNA be a text messaging system?
RNA is similar to DNA in structure except that uracil replaces thymine as one of the four bases. Also, it is fragile, compared to DNA. It can degrade in minutes without some protection.
Outside of a cell, it uses a bubble envelope for protection. At one time, these envelopes were thought to be the cell’s trash, getting ejected:
Then, in the early 2000s, experiments led by Hadi Valadi, a molecular biologist at the University of Gothenburg, revealed that the RNA inside some EVs didn’t look like trash. The cocktail of RNA sequences was considerably different from those found inside the cell, and these sequences were intact and functional. When Valadi’s team exposed human cells to EVs from mouse cells, they were shocked to observe the human cells take in the RNA messages and “read” them to create functional proteins they otherwise wouldn’t have been able to make.
Valadi concluded that cells were packaging strands of RNA into the vesicles specifically to communicate with one another. “If I have been outside and see that it’s raining,” he said, “I can tell you: If you go out, take an umbrella with you.” In a similar way, he suggested, a cell could warn its neighbors about exposure to a pathogen or noxious chemical before they encountered the danger themselves.
“Cells Across the Tree of Life Exchange ‘Text Messages’ Using RNA,” September 16, 2024
RNA is widely read…
Since then, she says, much evidence has supported his theory. Some researchers wonder if RNA can be understood as a common language that can be read among cells of widely different life forms:
In 2024, new studies have exposed additional layers of this story, showing, for example, that along with bacteria and eukaryotic cells, archaea also exchange vesicle-bound RNA, which confirms that the phenomenon is universal to all three domains of life. Another study has expanded our understanding of cross-kingdom cellular communication by showing that plants and infecting fungi can use packets of havoc-wreaking RNA as a form of coevolutionary information warfare: An enemy cell reads the RNA and builds self-harming proteins with its own molecular machinery.
When “transient” is a real benefit
Melchor points out the advantage RNA offers cells for communication.
As a message, RNA is transient. This is a feature, not a bug: It can have only short-term effects on other cells before it degrades. And since the RNA inside a cell is constantly changing, “the message that you can send to your neighboring cell” can also change very quickly, Erdmann said. In that sense, it’s more like a quick text message or email meant to communicate timely information than, say, runes etched in stone or a formal memo on letterhead.
Because RNA is of very ancient origin, Melchor suggests, most organisms have likely retained the ability to read its simple code. But that fact alone can lead to complex interactions: “a recipient cell can open and interpret the message before realizing it could be dangerous, the way we might instinctively click a link in an email before noticing the sender’s suspicious address.”
She describes several instances of life forms using this feature as warfare against other ones. For example, the mustard plant greets a damaging fungus in precisely this way: Once the RNA message is opened, the fungus manufactures proteins harmful to itself.
University of Edinburgh researcher Amy Buck tells Melchor, “We should be inspired with how incredibly powerful and dynamic RNA is, and how we’re still discovering all the ways that it shapes and regulates life.”
Indeed. But there is something else that we might also want to notice.
What is the origin of the information that the RNA language conveys?
The RNA research that Melchor describes shows, as does much other research, that we live in a universe full of information. Its origin requires some source of meaning that matter and energy do not by themselves account for.
The origin and development of life cannot really be separated from the origin and development of information. The Big Bang and its outcomes may explain the origin of matter and energy but do they really explain the origin of information?
Information is conveyed by means of matter and energy but is in itself immaterial.
As design theorist William Dembski points out, information is fundamentally a relational notion. Among other things, it is a relationship between realized and unrealized possibilities. It is created by ruling out possibilities — which do not exist until realized.
The vast amount of information we find in life forms is a constant stream of connections made, of messages sent and received, even though most participants are not even conscious — although the connections do provide a substrate for consciousness of various types.
Can the complex co-operation, competition and sometimes warfare between life forms, conveyed through RNA messaging, be explained by Darwinian natural selection, acting on random mutations? Underlying such a view is a key assumption: that the information doesn’t, at bottom, exist. It is simply the movement of chemicals that create the illusion of design and purpose in our minds.
Famously, philosopher Daniel Dennett (1942–2024), invested his career in popularizing the idea that the minds that do the interpreting are illusory too. The trouble with his thesis is that, if everything is an illusion, nothing is.
As I’ve said before, the big controversy in science today is fast becoming a conflict — not between Darwinism and design in nature but between panpsychism and design in nature. Either the cells are intelligent or something beyond nature is. Let the games begin.