WHAT IS THE CENTRAL DOGMA OF MOLECULAR BIOLOGY? - BIOLOGY - 2025

The central dogma of molecular biology says that genetic material is transcribed into RNA and then translated into protein.

That is, in this discipline it is considered that the flow of information in organisms only goes in one direction: genes are transcribed into RNA.

This approach was made public in 1971, a few years after the transmitter function of the deoxyribonucleic acid (DNA) molecule had been discovered.

Francis Crick, was the scientist who exposed this idea by describing the transfer of genetic information using the information that was available then.

In parallel, Howard Temin proposed the possibility that an RNA could serve for DNA synthesis, as an exceptional but possible case.

This proposal did not catch on among the scientific community given the popularity of the dogma and because it was a process that would only be possible in cells infected by certain RNA viruses.

What does molecular biology study?

Molecular biology is, according to the Human Genome Project, "the study of the structure, function, and composition of biologically important molecules."

More specifically, molecular biology studies the molecular bases of the processes of replication, transcription and translation of genetic material.

Molecular biologists are trying to understand how cell systems interact in terms of DNA, RNA, and protein synthesis.

Although a molecular biologist uses techniques exclusive to his field, he combines them with others more typical of genetics and biochemistry.

Much of his method is quantitative, which is why there has been a high interest in the interface of this discipline and computer science: bioinformatics and / or computational biology.

Molecular genetics has become a very prominent subfield within molecular biology.

How does the central dogma of molecular biology work?

For those who defended this idea, the process was as follows:

Transfer of genetic information

The works of Gregor Mendel, in 1865. They signified an antecedent of the genetic inheritance that allows the DNA molecule, discovered between 1868 and 1869 by Friedrich Miescher.

Knowing the primary structure of DNA, allowed to know the synthesis process of the same and the way in which genetic information is encoded.

Replication of DNA

Then, the discovery of the secondary structure of DNA allowed us to model the double helix structure that is so well known today, but was a revelation at the time.

This revelation gave rise to the exploration of DNA replication, a vital process for cell survival that consists of division by mitosis, and which requires prior replication to conserve genetic material.

In 1958, Matthew Meselson and Frank Stahl affirmed that this replication was semi-conservative, since one of the chains is conserved, and that it serves as a template to synthesize its complement.

In this process, proteins such as DNA polymerase intervene, which adds nucleotides to the new chain using the original as a template.

DNA transcription

The discovery and description of this process answered the question of how DNA and proteins were related when they were in different places in cells.

The intermediate molecule that made this relationship possible turned out to be mature ribonucleic acid (RNA).

Specifically, RNA polymerase is the molecule that takes a template from one of the DNA strands, from which it forms a new RNA molecule. This occurs following the complementarity of bases.

In other words, it is a process in which the information from a section of DNA is reproduced in a piece of messenger RNA (mRNA).

The product of transcription is a mature strand of messenger RNA (mRNA).

RNA translation

In the final phase, the mature messenger RNA (mRNA) serves as a template for protein synthesis. Here the ribosomes intervene together with molecules of the transmission RNA tRNA.

Each ribosome interprets a trio of mRNA nucleotides, called a codon, and is complemented by the anticodon that each tRNA has.

This tRNA carries with it the amino acid that will fit into the polypeptide chain, so that it folds into the correct conformation.

In prokaryotic cells, transcription and translation can occur together, while in eukaryotic cells, transcription occurs in the cell nucleus and translation occurs in the cytoplasm.

The overcoming of Dogma

In the 1960s it had been seen that some viruses made it possible for the cell to “reverse transcribe” RNA to DNA.

Such was the case of the Reverse Transcriptase (RT) protein, responsible for using the template HIV RNA to synthesize a double strand of proviral DNA to integrate it into cellular DNA.

This protein is currently used in laboratories and earned Howard Temin, David Baltimore, and Renato Dulbecco the Nobel Prize in Medicine in 1975.

On the other hand, there are other viruses made of RNA, capable of synthesizing an RNA chain from the one they already have.

Another possible cause of this alteration can be found in defects in the regulatory sequences of genes affecting the expression of the protein and the transcription process of one or more genes.

These discoveries have been the basis of much research in the field of molecular biology such as those related to cancer disease, neurodegenerative diseases or synthetic biology.

In short, the central dogma of molecular biology was an attempt to explain how the flow of genetic information works in an organism.

This attempt was overcome, after several years of scientific research that allowed us to offer an explanation closer to reality.

References

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