DNA Function Advantage over RNA
Country: United States
Date: April 2006
Why does DNA make a better material than RNA for
storage of genetic information?
The most important by far is that DNA is typically double stranded. This
has a number of advantages, the most immediate being when one strand breaks
the entire molecule doess not fall apart...there are other advantages...if
an error is made in one strand on one base the other strand is still there
in its original order to help maintain the original sequence on the opposite
strand when a correction enzyme comes along to clip out the mismatch.
Both can serve as genetic material; many viruses use RNA as their genetic
material. DNA probably evolved as the genetic material for cells so that RNA
could be used as messenger RNA which carries the information for protein
synthesis to the ribosomes. This way, many "copies" of the gene can be made
so that more protein molecules can be synthesized in a short period of time.
Also, the mRNA is metabolically unstable because it is rapidly broken down
by RNAse. DNA must be stable so RNA had to evolve to fulfill this function.
Ron Baker, Ph.D.
Both DNA and RNA have the same coding capacity. They both are polymers
with similar potential length. The answer to your question lies in a
form of DNA that commonly exists in all living organisms but is not
really common with RNA. Some viruses are exceptional because they exist
with a single strand of DNA or with a double strand of RNA.
Jim Tokuhisa, Ph.D.
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Update: June 2012