About central dogma in biology

Central dogma in biology dates back to 1958, when F. Crick proposed a theory that explained the flow of information within the organism. Moreover, it can be represented in the form of the flow diagram, as you can see right here in the picture, which I borrowed from the book Genetic engineering - dreams and nightmares. The information flow starts from nucleic acids, which are building rocks of DNA, our genetic code. That's all in the nucleus of basically every cell.

 

In there, DNA strand is split apart, and one strand leaves nucleus as messanger RNA, or mRNA. This molecule carries information about how to make various proteins needed for the body. So out of nucleus, and in the cytoplasm, mRNA is processesed and used for protein synthesis.

 

Protein synthesis comes in four structural steps called primary, secondary, tertiary, and quaternary structures. Primary structure consists of the chain of amino acids, and secondary is already building blocks like alpha-helixes or beta-pleated sheets. Those are then used in numerous combinations to create many different proteins. Those are then transported out of the cell into the place where it will be used for building or regenerating the new or existing tissue. And that's how the organism is built up.

 

 

DISCOVERY OF REVERSE TRANSCRIPTASE

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Now we get to the point where this dogma becomes a dogma.This way of information flow was thought to be not revearsable, or simply put, it's only one-way street. But the scientific research and fast progress in genetic engineering proved that the opposite way is also possible. Study of retroviruses like Rous sarcoma virus, or bacteria like Escherichia coli (E. coli), showed that those micro-organisms contain an enzyme, which is able to create brand new DNA code. This enzyme is called reverse transcriptase.

 

In order to do this, it first creates so called complimentary DNA, or shortly cDNA. This is then compared with mRNA, because this serves as a template for reverse transcriptase. Here is where evolution and natural selection will play a part for a while, and the end/best result is then doubled and twisted by DNA polymerase - another enzyme. Well, and the new DNA is ready.

 

The research on viruses and bacteria has been proved to be very beneficial in many ways. For example many enzymes and hormones can be synthetically produced in laboratories using bacteria or viruses. This has been a huge relief from getting all those needed substances by natural ways, that is from people. Pharmacology experienced a big boom since, and is still evolving and developing, along with genetic engineering, as one of the leading research programs to date.