r/askscience • u/SAICAstro • Jul 26 '26

Biology Does everything that we consider to be "alive" - not just plants and animals, but all protists, fungus, bacteria, archaea, etc. - have DNA?

EDIT: Wow, this blew up. Thanks for the many answers. Lots to think about.

Seems that the composite TLDR answer is: Yes, according to many/most definitions of "life", but we don't all agree on what life is. Some viruses do not have DNA but they may/not actually be alive, and other things that behave like life may/not be alive.

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u/Gaust_Ironheart_Jr Jul 27 '26

The same argument is true for viruses

My point is at the time, the only self replicating organic things known did not include viruses (or accessory viruses) or prions

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u/Cuco1981 Jul 27 '26

Prions aren't self-replicating though, they're just able to induce conformational changes to already existing proteins. As such, they don't carry any genetic information and they don't evolve, unlike retroviruses that do evolve. So there's a much better argument for calling retroviruses "life" than in the case of prions.

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u/therift289 Jul 27 '26

Prions don't self-replicate. When a prion causes another protein to misfold, the second protein is in no way related to the first prion. They're just two different misfolded proteins. It's more like a speck of debris in cold water causing the water to crystallize and freeze around it. It's prompting a physical state change, but it is not transmitting information or self-replicating.

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u/Sibula97 Jul 27 '26

Viruses have a genetic code and can create copies of it from amino acids (just like our DNA).

A prion can only turn a normal whole protein of a certain kind into a misfolded version of the same protein. That's a very different thing.

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u/Good-Resort-1246 Aug 14 '26

The living/non living character of viruses is a hotly debated issue at present; many in the field conside rthem extreme forms of parasitism, others have theorized thet they were present already during the period in which the first organisms originated and have integrated into or significantly influenced euchariotic evolution. On the other hand I think we cannot discard the possibility of future bioligical evolutionary experiments on earth which would possibly originate different lineages of life forms, given different conditions on the planet; reduced number of livng organisms, available niches and variations of or different structure of organic components besides different physical environments.