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I wonder are there hereditary materials other than DNA deoxyribonucleic acid (may be on different planets).

In addition, I learned in my high school that carbon and silicon are similar. Is it possible to have hereditary materials with silicon replacing carbon.

Why and why not?

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  • $\begingroup$ Welcome to Biology.SE! What research have you done before asking it here? There are alternatives to DNA on this planet too... $\endgroup$ Commented Jul 9, 2017 at 6:24
  • $\begingroup$ Irecommend picking a single question, either ask about alternatives to DNA in carbon based life or about the possibility to silicon based life. The silicon based life question might be better for worldbuilding than here since it is much more hypothetical. $\endgroup$
    – John
    Commented Jul 9, 2017 at 15:17

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First of, depending on your definition of life (which is a matter of philosophy, not science) you may even accept as living something that has not heritable information passed onto 'offspring'. But let's consider only those hypothetical life forms who would have heritable information.

Of course, it is possible for different life forms to use some other mean of transferring heritable information. In fact, there are life forms based on RNA instead of DNA on earth (see RNA virus) and it is even thought by many that life first evolved using RNA and not DNA (see RNA world hypothesis).

To go further in this discussion you should have a look at wikipedia > Hypothetical types of biochemistry (I got the link from @RoniSaiba 's answer).

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    $\begingroup$ Typically virus, are not regarded as lifeforms as they cannot replicate on their own without a host. But your point about RNA as a heritable molecule is correct. $\endgroup$ Commented Jul 9, 2017 at 23:12
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    $\begingroup$ Exobiologists definitely consider viruses as being living things of interest. Physiologist might not consider a virus alive due to absence of metabolism (although see mamavirus and among others). Note also that saying they cannot replicate on their own without a host is not a very good distinction for defining what is living. Parasitoid wasps cannot reproduce without a host either, yet everyone would agree they are alive. But I agree that not everyone would agree viruses are alive. See this post for discussion. $\endgroup$
    – Remi.b
    Commented Jul 12, 2017 at 16:26
  • $\begingroup$ The post has a top answer, which explains my point in detail. Virus rely on the host to provide the basic molecular machinery they need to replicate; ribosomes for protein synthesis and the metabolism of the host to provide the basic building blocks of life, amino acids and nucleotides. Thus without a host, a virus cannot maintain itself and will be destroyed over time. $\endgroup$ Commented Jul 13, 2017 at 0:17
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I suggest a read of this wikipedia article [Hypothetical types of biochemistry].1
From my understanding of bond energies (which are proportional to the stability of a molecule) it seems that Si based compounds are less thermo-stable. Given how planets form from molten states it is more likely that carbon based life evolves first and outcompetes the emerging non carbon lifeforms.

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