When RNA is stable enough to be the genetic material for few viruses why can't it be for other organisms?
RNA is less chemically stable than DNA, making it less ideal for reliably sustaining information in the long term. RNA viruses and retroviruses mutate rapidly because of their RNA-based genome. This makes it a challenge to medicate against them, as they will quickly develop resistant mutations to any single drug. (It also has to do with the error-prone polymerase they use, so it’s not only the instability of the RNA in itself).
But these viruses aren’t necessarily unique in having an RNA genome. A popular hypothesis on early life states that pre-living self-replicators were RNA-based —that is, the very old self-replicating systems which would eventually evolve into what we now recognize as “life”, might have been made from RNA.
Before having evolved the complicated biochemical machinery necessary for our highly specific DNA-protein system, earlier replicators would have also needed to carry hereditary information and perform specific catalysis. RNA molecules can perform both of those general functions quite well. In fact, they do perform those functions in current cell chemistry. RNA carries information as mRNA (and some other situations), and performs catalysis in ribosomes and tRNA (and some other situations). Nucleic acids and close derivatives thereof are also used throughout many biochemical pathways (most notably in ATP).
Notably, RNA and nucleic acids are particularly prevalent in pathways that perform our most crucial (and therefore likely oldest) functions like replication and general metabolism. This is often interpreted as an artifact from an old RNA-based prebiotic replicator, which later on evolved to use more efficient DNA and proteins.
RNA isn’t very stable, so only very simple organisms which only carry a short string of genetic material, and which can tolerate a lot of mutations, still use it.
RNA is less chemically stable than DNA, making it less ideal for reliably sustaining information in the long term. RNA viruses and retroviruses mutate rapidly because of their RNA-based genome. This makes it a challenge to medicate against them, as they will quickly develop resistant mutations to any single drug. (It also has to do with the error-prone polymerase they use, so it’s not only the instability of the RNA in itself).
But these viruses aren’t necessarily unique in having an RNA genome. A popular hypothesis on early life states that pre-living self-replicators were RNA-based —that is, the very old self-replicating systems which would eventually evolve into what we now recognize as “life”, might have been made from RNA.
Before having evolved the complicated biochemical machinery necessary for our highly specific DNA-protein system, earlier replicators would have also needed to carry hereditary information and perform specific catalysis. RNA molecules can perform both of those general functions quite well. In fact, they do perform those functions in current cell chemistry. RNA carries information as mRNA (and some other situations), and performs catalysis in ribosomes and tRNA (and some other situations). Nucleic acids and close derivatives thereof are also used throughout many biochemical pathways (most notably in ATP).
Notably, RNA and nucleic acids are particularly prevalent in pathways that perform our most crucial (and therefore likely oldest) functions like replication and general metabolism. This is often interpreted as an artifact from an old RNA-based prebiotic replicator, which later on evolved to use more efficient DNA and proteins.
RNA isn’t very stable, so only very simple organisms which only carry a short string of genetic material, and which can tolerate a lot of mutations, still use it.
