# Alternatives to cellular carbon based lifeforms [duplicate]

In my up coming novel this fall, I got the human crews as well as some humanoid alien species working and living onboard a FTL starship exploring an uncharted cluster of neutron stars and black holes. As the story progresses the starship will visit strange and unfamiliar worlds and add diversity to the existing crews, I'm seeking a carbon based living organism which doesn't share our cell structure or DNA for reproduction and I also need the unique environment to sustain such a lifeform. Last but not least how can it stay onboard the vessel without jeopardizing its life?

## marked as duplicate by JDługosz, Azuaron, Brythan, John Dallman, HohmannfanNov 5 '16 at 20:52

• Cells and DNA only seems most probable because it's happened. – Mołot Nov 5 '16 at 8:47
• Besides the existing question here, ask Google for alternatives to dna. – JDługosz Nov 5 '16 at 9:53
• @JDługosz I posed a question about a logical inconsistency and he pulled a Men in Black reference – dot_Sp0T Nov 5 '16 at 10:02
• @dot_Sp0T But not in the Southern Hemisphere where it is Spring. The coming Autumn will then be in 2017. – a4android Nov 5 '16 at 10:49
• This question would be clearer if updated based on the knowledge in the "Alternatives to DNA" question. As stated, it still seems to be asking for the duplicate information. If you remove that part of the question and instead replace it with your decision (even if only leaning), that would simplify this question. – Brythan Nov 5 '16 at 11:14

The only known non-cellular lifeforms are the viruses.

A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.

This suggests the most probable environment where a virus can exist, is inside the living cells of other organisms. This might be extended to some sort of generalized organic system. OK. A mass of organic or biological material, possibly undifferentiated, rather like a living blob or perhaps an organic pool.

The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity.[7] Viruses are considered by some to be a life form, because they carry genetic material, reproduce, and evolve through natural selection. However they lack key characteristics (such as cell structure) that are generally considered necessary to count as life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life",[8] and as replicators.

Source for the above quotations is the Wikipedia entry on viruses.

The OP has been given references to sources of information about alternatives to DNA, in the comments above, these do not need to be duplicated in this answer.

• While I agree that viruses fit the OP's criteria, they may not have the level of intelligence or size to interact with a ship crew. Would there be a way for viruses to evolve to or reach that point? – Zxyrra Nov 5 '16 at 15:51
• See life without cells. What you describe is known as a cell-free culture. – JDługosz Nov 5 '16 at 19:07
• @JDługosz: Well, well. Cell-free cultures are new to me. To think I only hypothesized their existence & there they are in the real world.. I really should have made the connection to a syncytium. Always something new to learn. – a4android Nov 6 '16 at 3:00
• @Zxyrra: That's why I immersed the viruses in, what I now known, as a cell-free culture. Provided it can develop sensoria and some information processing capacity (plus memory & communications channels) it should be on the way to gaining sapience. This concept gives the OP something to build on for an acellular lifeform. – a4android Nov 6 '16 at 3:03
• Well, I hope you upvoted the referenced post! ☺ – JDługosz Nov 6 '16 at 4:00