XNA Alternative


DNA and RNA have always been considered miracle molecules thanks to their ability to self-replicate and create life. Everyone thought that they were the only molecules that could carry information on how to code for an organism and pass this down for generations. But what if I told you there were other molecules capable of doing the same thing?

This group of molecules is called XNAs (Xeno Nucleic Acids) and they all are a polynucleotide strands but each with a different repeating monomer. They still have a base and a phosphate group attached; what changes is the sugar in them. Whilst DNA uses deoxyribose and RNA uses ribose, XNA can use a wide variety of sugars, like theorose, or other unrelated chemicals, like peptides.

DNA XNA

This is a normal DNA strand – XNA is the same but with a different sugar in the nucleotide

Not only do they copy the structure of a nucleotide and therefore form a nucleic acid, but they can also store information in the form of bases. However, to make XNA carry bases in a desired order, scientists have to use an enzyme that copies the coding from a DNA strand and passes it onto an XNA strand. Once there, another enzyme can read the bases in the XNA and copy them onto DNA, and if needed, back to XNA. This means that an old XNA can technically pass information to a new XNA molecule, even if it uses an intermediate molecule; this process is basically evolution.

But this discovery is from back 2012. The current news involves XNA being able to act as enzymes, apart from encoding possible genetic information. They still can’t form copies of themselves in the traditional sense, but they can manipulate RNA and even add XNA fragments to an XNA strand. The fact these molecules are enzymes and can modify themselves to some extent makes it more feasible that at some point they will be able to self-replicate, and behave just like DNA did, to evolve into a new type of life.

It is also further proof showing that XNA is a viable alternative to both DNA and RNA, and that the reality that all living organisms we know use these nucleic acids could be arbitrary. In fact, it could be perfectly possible than in other galaxies, organisms use XNAs instead of DNA. Of course, this is only a theory, and we have to take into account the conditions of an environment without any life. RNA and DNA could have developed because they were more likely to appear in the first place, for a reason unbeknownst to us yet.

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2 comments on “XNA Alternative

    • I’m glad to have introduced you to such a creative and curious experiment! Hope you find it even more interesting as you explore it further. Please tell me if there’s anything especially worth sharing, we can even have a discussion 🙂

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