system
Given the following post, respond as if you're commenting on Reddit:
human
Why is RNA necessary?

I was curious as to the reason that RNA is necessary as an intermediate between DNA and proteins. It seems like it would be much easier to have DNA polymerases create single stranded DNA molecules and have ribosomes bind to this in order to create proteins. Why cant RNA function as the long term storage of genetic material?
gpt
1) RNA is not used to permanently store genetic information because DNA is more chemically stable. At the beginning of life on Earth, RNA was used as the genetic storage material, but use of DNA proved to be more stable and reliable and was selected for.
2) mRNA is still used as the mediator between DNA and protein because of the ribosome. Ribosomes are comprised of RNA and protein, and require RNA for translation. Apparently, there was no evolutionary benefit to using DNA- based ribosomes (deoxyribosomes?), so the machinery never changed.