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Funnily enough, it is probably the other way round!

Scientists believe, for various reasons, that RNA came first, and that there was an "RNA world" before DNA evolved. If this idea is correct, uracil was a component of nucleic acids before thymine.

When DNA evolved, thymine may have proved a preferable material for storing genetic information because of its much greater stability; RNA breaks down relatively quickly, but DNA is stabilized by its double-stranded form. RNA is easily hydrolised than DNA.

It is interesting to note that in our own bodies we can synthesize RNA from simpler compounds, but to make DNA we first build RNA nucleotides, then convert them. We remove one oxygen atom from the ribose component of the nucleotide, to form deoxyribose. Then, if the base is uracil, we add a methyl group to it to form thymine.

But this leaves the question: what advantage does thymine have over uracil in DNA? One suggestion is this: cytosine (C) occasionally converts into uracil (U) by deamination. If this U is not removed, at the next replication it will act as a template for an adenine (A) on the new strand, and there will have been a mutation from G to A. Having thymine (T) as the regular base in DNA makes it easy for a cell to spot a deamination, because U should not be there at all. The cell then removes the U with a DNA repair enzyme (e.g. uracil glycosylase).
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Related Questions

Does uracil replace thymine in RNA?

Yes, uracil replaces thymine in RNA.


What does uracil replace in RNA?

Uracil replaces thymine in RNA.


What base does uracil replace in RNA?

Uracil replaces thymine in RNA.


What does uracil replace in RNA molecules?

Uracil replaces thymine in RNA molecules.


What is the base of RNA in place of thymine which bonds with adenine?

The nitrogen base uracil takes the place of thymine in RNA. So in RNA, uracil pairs with adenine.


What nucleotide replaces thymine?

Uracil replaces Thymine in DNA. Adenine and Thymine go together while Cytosine and Guanine go with each other in DNA. But, in RNA, Thymine is replaces with Uracil. So not Adenine and Uracil go together, while Cytosine and Guanine pair up.


What is a pyrimidine base found in RNA but not in DNA?

Thymine


Does RNA contain the nitrogen base uracil?

NO. RNA contains URACIL while in DNA it is THYMINE, the uracil replaces the thymine.


What replaces thymine?

Uracil replaces Thymine in RNA. Uracil can't be in DNA and Thymine can't be in RNA.


When does uracil replace thymine in DNA replication?

Uracil replaces thymine in DNA replication during the process of transcription, where RNA polymerase reads the DNA template and incorporates uracil instead of thymine in the newly synthesized RNA strand.


What nitrogenous base is not found on DNA but is found on RNA?

Thymine is not found in RNA. It is instead replaced by Uracil.


Does RNA have uracil or thymine in its nucleotide structure?

RNA contains uracil in its nucleotide structure, not thymine.