The RNA world hypothesis proposes that when life first evolved, RNA both stored genetic information and directed the synthesis of proteins. According to the hypothesis, DNA evolved from RNA, and then it replaced RNA as the genetic storage molecule. Several observations that support the RNA world hypothesis are given below.
RNA stores genetic information.
RNA can replicate itself.
RNA is structurally similar to DNA.
RNA synthesizes proteins.
In contrast to RNA, DNA is not able to directly synthesize proteins nor can it replicate itself. However, according to the hypothesis, DNA was able to replace RNA as the genetic storage molecule.
Which additional observation, if true, would best support the RNA world hypothesis?
A.
The base uracil in RNA has less frequent mutations than the base thymine in DNA.
B.
RNA is less likely to have errors in replication than DNA because it can self-replicate.
C.
The ribose sugar in RNA is less likely to degrade than the deoxyribose sugar in DNA.
D.
RNA is less stable than DNA and has less precise mechanisms for repairing itself.
A. The base uracil in RNA has less frequent mutations than the base thymine in DNA.
This observation would support the RNA world hypothesis because it suggests that RNA, as the original genetic storage molecule, is more stable and less prone to mutations compared to DNA. This would imply that RNA was better suited to store genetic information in the early stages of life's evolution.