Central Dogma of Molecular Genetics

Restriction-Modification Systems of Bacteria

Cloning Vectors

cDNA Cloning

Clone Library Screening

DNA Sequencing

Southern and Northern Analysis

Exons and Introns

Polymerase Chain Reaction (or PCR)

Study Questions

Cloning and Molecular Analysis of Genes WWW Links

Genetic Topics

Central Dogma of Molecular Genetics

The most significant recent development in genetics has been the introduction of molecular tools for genetic analysis. These techniques are based on the Central Dogma of Molecular Genetics.


This diagram depicts the flow of genetic information from DNA into protein, the molecule most often associated with a specific phenotype. The three molecular events that maintain the genetic integrity and convert DNA information into a protein molecule are replication, transcription and translation. For some viral species, reverse transcription is also important. Each of th ese events are enzymatically driven and some of the enzymes involved in these steps are important for molecular studies. In particular these enzymes are:

  • DNA polymerase - synthesizes DNA from a DNA template; used to radiolabel DNA probespolymerase chain reaction and cDNA cloning
  • DNA ligase - forms a covalent bond between free single-stranded ends of DNA molecules during replication; used for DNA cloning
  • Reverse transcriptase - synthesizes DNA from a RNA template; used primarily for cDNA cloning
Although these enzymes are important for molecular cloning, they are not the only ones that are important. They are listed here primarily to emphasize that the study of the basic processes of life can also have an applied usage.

Copyright © 1997. Phillip McClean