It now seems certain that RNA was the first molecule of heredity, so it evolved all the essential methods for storing and expressing genetic information before DNA came onto the scene.

Is DNA evolved from RNA?

DNA can be considered as a modified form of RNA, since the “normal” ribose sugar in RNA is reduced into deoxyribose in DNA, whereas the “simple” base uracil is methylated into thymidine. ... The synthesis of DNA building blocks from RNA precursors is a major argument in favor of RNA preceding DNA in evolution.

How did DNA evolved from RNA?

The emergence of DNA genomes in the RNA world. ... In the first, protein enzymes evolved before DNA genomes. In the second, the RNA world contained RNA polymerase ribozymes that were able to produce single-stranded complementary DNA and then convert it into stable double-stranded DNA genomes.