Bioinformatics/The central dogma of molecular biology

I. Central Dogma of Molecular Biology Overview
The central dogma of molecular biology is an explanation of the flow of genetic information within a biological system. It was first stated by Francis Crick in 1956 and re-stated in a Nature paper published in 1970.

The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that such information cannot be transferred back from protein to either protein or nucleic acid.

The central dogma has also been described as "DNA makes RNA and RNA makes protein". However, the dogma also admits the reverse flow of information from RNA to DNA but not from proteins to DNA or RNA, as recalled by Francis Crick (1970). The dogma is a framework for understanding the transfer of sequence information between bipolymers sequential carrying information. There are 3 major classes of such biopolymers: DNA and RNA (both nucleic acids), and protein. There are 3×3 = 9 conceivable direct transfers of information that can occur between these. The dogma classes these into 3 groups of 3: 3 general transfers (believed to occur normally in most cells), 3 special transfers (known to occur, but only under specific conditions in case of some viruses or in a laboratory), and 3 unknown transfers (believed never to occur). The general transfers describe the normal flow of biological information: DNA can be copied to DNA (DNA replication), DNA information can be copied into mRNA (transcription), and proteins can be synthesized using the information in mRNA as a template (translation).