Module 7 : Concept of GENE, GENOME and GENE EXPRESSION

The centeral dogma of molecular biology.

• First proposed by Francis Crick in 1958. • According to this dogma, DNA holds the coded hereditary information in the nucleus. The sequence involved in the expression of hereditary characteristics runs from DNA to RNA to protein.

• Thus, the Central Dogma involves three important biomolecules , namely DNA, RNA, and proteins. • It also involves three processes, namely DNA replication, transcription, and translation through protein synthesis. • It forms the basis of storage, transmission, and expression of hereditary information.

The Modified Central Dogma :

An important revolution in the Central Dogma came with the discovery of retroviruses, which transcribed RNA into DNA using an enzyme called reverse transcriptase. This lead to an exception to the Central Dogma which was later modified as shown below :