Final answer:
DNA likely became the primary means of transmitting genetic information due to its chemical stability and reduced mutation rates compared to RNA, making it a superior medium for low-error replication and favored by natural selection.
Step-by-step explanation:
Once DNA evolved, it is hypothesized that it became the primary means of transmitting genetic information due to its chemical stability compared to RNA. DNA's more stable structure meant that it was less prone to mutations, which could potentially lead to a higher fidelity of information storage and transmission. This stabilization is proposed to have made DNA a more reliable repository for the genetic code, and thus it would have been favored by natural selection.
According to the RNA world hypothesis, early life was likely RNA-based due to RNA's ability to both store genetic information and catalyze chemical reactions. Yet, as proteins began to evolve with the ability to catalyze more diverse and efficient reactions, they could have assumed the roles initially played by RNA. During this evolutionary juncture, RNA could have been used as a template to synthesize DNA via reverse transcriptase-like enzymes, marking the transition from an RNA world to a DNA world.
Once inheritance mechanisms were established through DNA, entities with this molecule would be subject to the principles of evolution. As such, those that reproduced more effectively with DNA would have been selected for, displacing less efficient reproducers over time. The transformative experiments by Chase and Hershey that pinpointed DNA as the genetic material bolstered the scientific shift towards DNA as the molecule responsible for heredity.