Cell biology Extraterrestrial life Genetics Intelligent Design Origin Of Life

Should NASA look for viruses in space?

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rotavirus/Graham Beards (Gnu)

From Alex Barash at Slate:

The not-quite life forms have a bad rap. But they’re a reliable sign of life, and it would be exciting to find them in space.

For one thing, viruses are an excellent indicator for life itself: Wherever there’s life on Earth, there are viruses, too, and almost invariably in far greater numbers. Some scientists think that’s been true from the very beginning. While we know that RNA, the genetic material that makes up some viruses, came before DNA, the genetic material required by everything else, the fact that all modern viruses depend on cells to reproduce has led to something of a chicken-or-the-egg scenario. The NIH’s Eugene V. Koonin has spent decades investigating the evolution of life. In a landmark paper from 2006, he made the case for a “virus world”—an origin story in which viruses predated cells, only becoming intracellular parasites (losing the ability to replicate independently in the process) once they had bacteria and other lifeforms to prey on. It’s hard to know for sure whether this is how it played out—it’s clear that viruslike entities came before cells as we know them today, but no one has been able to confirm that modern viruses are their direct descendants. But even if the nature and extent of viruses’ involvement in the origins of life is still contentious, their role as drivers of current evolution is indisputable. As one report from the American Academy of Microbiology put it, “Without viruses, life on Earth would be very different, or perhaps there would be no life at all.”

Of course, finding viruses in outer space wouldn’t be the same as finding life. Stedman and his colleagues class them as indirect evidence of life, and the debate over what a virus actually is, considering its need to co-opt cellular machinery in order to reproduce, continues. (Renowned immunologist Sir Peter Medawar’s working definition was said to be “a piece of bad news wrapped up in a protein.”) Still, the researchers contend that “if a virion (or a viruslike particle) were to be unequivocally detected in an extraterrestrial sample, very few people would claim that this would not be evidence for life—wherever that sample was from.” This makes sense: If these hypothetical viruses, unlike the ones we’ve found so far on Earth, are actually self-sustaining, they do meet NASA’s criteria for a life form; if not, it means that an actual living organism must be nearby to play host. More.

Actually, it’s not clear that RNA came first. Nor is it clear that viruses precede life. A good case can doubtless be made for viruses being part of the scrap heap of existing life.

But no matter. If you think you can find viruses in space, boldly go.

See also: Why viruses are not considered to be alive

Another stab at whether viruses are alive

Phil Sci journal: Special section on understanding viruses

Why “evolution” is changing? Consider viruses

The Scientist asks, Should giant viruses be the fourth domain of life? Eukaryotes, prokaryotes, archaea… and viruses?

Viruses are alive.

and

Are viruses nature’s perfect machine? Or alive?

3 Replies to “Should NASA look for viruses in space?

  1. 1
    vmahuna says:

    “But no matter. If you think you can find viruses in space, boldly go.”

    Um, well, NO! If the feeble-minded folks desiring to look for useless junk in space (what the Rugrats refer to as “outside space”) intend to use MY tax dollars in NASA’s budget, then there ain’t no reason to even START such a search. Of course, if one of the feebs happens to have $1.4 billion USDs laying around, well, yeah, sure. By all means blow that wad on a privately funded SpaceX launch whose 2nd stage fails to separate and drags the alleged “satellite” back down for a fiery crash. The crash will probably tell humanity as much as the satellite would have.

  2. 2
    Tom Robbins says:

    The idea that viruses came before cellular life to me is laughable. So what, you had these randomly assembled proteins WITH RNA! So we are back to how this selfassmbled and WHY? Then it just waited around until life came, then “decided” to learn how to insert its code into the living cell IN ORDER that, like all other life, it seemed to have the “need” to make more of itself? Agency keeps popping up no matter where you turn, and you need everything intact to do anything useful. Instead of focusing on the unlikelihood of ONE modest sized protein self-assembling, we should focus on if it self-assembles is it of any use? Can it do work? AND, in order to do work proteins typically need other proteins and enzymes or they are useless. Similarly, it is not just the bizarre claim that DNA self assembled along the way, containing immaterial digital code, but it MUST HAVE the mechanisms already in place that understand, can read the code and convert it into a particular piece of a protein, that requires more in the chain and 20 other processes, in real time, to make it of any use!! The “Odds” become irrefutable small, ridiculously small, if we consider, not just one protein, or a strand of DNA, BUT also a 1.USEFUL STRAND OF DNA OR a USEFUL protein and 2. The other mechanisms that must be there to make all that happen. THEN YOU MUST have the facility to perfectly separate the chromosome pairs, and split the cell, get it right the very first time – all this has to be in place (and much more in reality), or NOTHING HAPPENS..

  3. 3
    Tom Robbins says:

    The fact that the theory resists change, even though we now know just how complex the cell is, should be a red flag – as we uncover tons of completly new evidence, that does NOT support the accepted theory, the theory is simply wrong – going from thinking the cell was a simple bag of goo, to a digital read/write system – the comatose watchmaker can’t get anything off the ground, nor maintain it. The comostose watchmaker may kill off those that are sick, that’s about it.

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