Central Dogma of Molecular Biology (Series)

By: Bijay Dhungel , MSc

DNA is found inside the nucleus in the chromosomes whereas the site of protein synthesis is outside the nucleus in the cytoplasm. Thus, direct production of protein from the DNA sequence is not possible. Exceptions exist, for example prions or prion-like proteins. The lack of exist of cellular machinery that can synthesize proteins directly from DNA maybe also due to the fact that RNA evolved before DNA. In fact, convincing evidences can be found which suggest that DNA is result of evolution of RNA to store the information in a safer manner i.e. for survival. In any case, central dogma of molecular biology is the backbone of molecular biology upon which today’s science exists. It shows the flow of information from DNA to protein. First postulated by Francis Crick (co-receiver of Noble prize in physiology and medicine for discovering the structure of DNA), the central dogma states that sequence of bases in DNA determine the sequence of bases in RNA (which is also a polymer of ribose nucleotide different from DNA) by a process called transcription, this sequence of RNA polymer then determine the sequence of amino acids in a protein. Protein is a polymer of amino acids.  There have been many modifications to the central dogma. For e.g. reverse transcription i.e. formation of DNA from RNA has been found and so on. However, the basic principle is still among the most widely seen phenomenon.

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Central Dogma: DNA can duplicate (replication), make RNA (transcription), this RNA is transported to the cytoplasm where it is used by the cellular machinery for translation (synthesis of protein)

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