(a) One version of Francis Crick’s sketch of the central dogma, showing information flow between biological molecules. The circular arrow represents DNA replication, the central straight arrow represents the transcription of DNA into RNA, and the right arrow the translation of RNA into protein. (b) More detailed sketch showing how the two strands of the DNA double helix are independently replicated, how the two strands are disassociated for transcription, and how the messenger RNA (mRNA) is translated into protein at the ribosome.