Information flow in biological systems The central dogma of molecular biology was first enunciated by Francis Crick in 1958[1] and re-stated in a Nature paper published in 1970:[2] Image File history File links Download high-resolution version (1083x1084, 252 KB) Flow of information in biological systems. ...
Image File history File links Download high-resolution version (1083x1084, 252 KB) Flow of information in biological systems. ...
Francis Harry Compton Crick OM FRS (8 June 1916 – 28 July 2004) was an English molecular biologist, physicist, and neuroscientist, who is most noted for being one of the co-discoverers of the structure of the DNA molecule in 1953. ...
Year 1958 (MCMLVIII) was a common year starting on Wednesday of the Gregorian calendar. ...
Nature is one of the most prominent scientific journals, first published on 4 November 1869. ...
1970 (MCMLXX) was a common year starting on Thursday. ...
- POSTLEWAITE IS A TOOL The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that such information cannot be transferred back from protein to either protein or nucleic acid.
In other words, 'once information gets into protein, it can't flow back to nucleic acid.' Molecular biology is the study of biology at a molecular level. ...
The dogma is a framework for understanding the transfer of sequence information between sequential information-carrying biopolymers, in the most common or general case, in living organisms. There are 3 major classes of such biopolymers: DNA and RNA (both nucleic acids), and protein. There are 3×3 = 9 conceivable direct transfers of information that can occur between these. The dogma classes these into 3 groups of 3: 3 general transfers (believed to occur normally in most cells), 3 special transfers (known to occur, but only under abnormal conditions), and 3 unknown transfers (believed to never occur). The general transfers describe the normal flow of biological information: DNA can be copied to DNA (DNA replication), DNA information can be copied into mRNA, (transcription), and proteins can be synthesized using the information in mRNA as a template (translation).[2] In mathematics, a sequence is a list of objects (or events) arranged in a linear fashion, such that the order of the members is well defined and significant. ...
The ASCII codes for the word Wikipedia represented in binary, the numeral system most commonly used for encoding computer information. ...
This article or section does not adequately cite its references or sources. ...
This article or section does not cite any references or sources. ...
The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ...
Ribonucleic acid (RNA) is a nucleic acid polymer consisting of nucleotide monomers, that acts as a messenger between DNA and ribosomes, and that is also responsible for making proteins out of amino acids. ...
Highly simplified diagram of a double-stranded nucleic acid. ...
A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
It has been suggested that DNA replicate, Replisome, Replication fork, Lagging strand, Leading strand be merged into this article or section. ...
The interaction of mRNA in a eukaryote cell. ...
A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ...
Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ...
Biological sequence information
- Main article: Primary structure
Biopolymers are biological polymers. That is, they are molecules made up of building blocks known as monomers. The biopolymers DNA, RNA and proteins, are linear polymers (ie: each monomer connects to at most two other monomers). The sequence, or arrangement of their monomers, effectively encodes information. The transfers of information described by the central dogma are faithful, deterministic transfers, wherein one biopolymer's sequence is used as a template for the construction of another biopolymer with a sequence that is entirely dependent on the original biopolymer's. A protein primary structure is a chain of amino acids. ...
A polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ...
In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ...
In mathematics, a sequence is a list of objects (or events) arranged in a linear fashion, such that the order of the members is well defined and significant. ...
The term deterministic may refer to: the more general notion of determinism from philosophy, see determinism a type of algorithm as discussed in computer science, see deterministic algorithm scientific determinism as used by Karl Popper and Stephen Hawking deterministic system in mathematics deterministic system in philosophy deterministic finite state machine...
General transfers of biological sequential information -
Table of the 3 classes of information transfer suggested by the dogma | General | Special | Unknown | | DNA → DNA | RNA → DNA | protein → DNA | | DNA → RNA | RNA → RNA | protein → RNA | | RNA → protein | DNA → protein | protein → protein | Image File history File links Cdmb. ...
Image File history File links Cdmb. ...
DNA Replication -
As the final step in the Central Dogma, to transmit the genetic information between parents and progeny, the DNA must be replicated faithfully. Replication is carried out by a complex group of proteins that unwind the superhelix, unwind the double-stranded DNA helix, and, using DNA polymerase and its associated proteins, copy or replicate the master template itself so the cycle can repeat DNA → RNA → protein in a new generation of cells or organisms. It has been suggested that DNA replicate, Replisome, Replication fork, Lagging strand, Leading strand be merged into this article or section. ...
A Superhelix is a molecular structure in which a helix is itself coiled into a helix. ...
3D structure of the DNA-binding helix-hairpin-helix motifs in human DNA polymerase beta A DNA polymerase is an enzyme that assists in DNA replication. ...
It has been suggested that DNA replicate, Replisome, Replication fork, Lagging strand, Leading strand be merged into this article or section. ...
Transcription -
Transcription is the process by which the information contained in a section of DNA is transferred to a newly assembled piece of messenger RNA (mRNA). It is facilitated by RNA polymerase and transcription factors. In eukaryote cells the primary transcript (pre-mRNA) is often processed further via alternative splicing. In this process, blocks of mRNA are cut out and rearranged, to produce different arrangements of the original sequence! A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ...
The life cycle of an mRNA in a eukaryotic cell. ...
RNAP from pictured during elongation. ...
In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ...
Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta Opisthokonta Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ...
Various modes of alternative splicing Alternative splicing is the process that occurs in eukaryotes in which the splicing process of a pre-mRNA transcribed from one gene can lead to different mature mRNA molecules and therefore to different proteins. ...
Translation -
Eventually, this mature mRNA finds its way to a ribosome, where it is translated. In prokaryotic cells, which have no nuclear compartment, the process of transcription and translation may be linked together. In eukaryotic cells, the site of transcription (the cell nucleus) is usually separated from the site of translation (the cytoplasm), so the mRNA must be transported out of the nucleus into the cytoplasm, where it can be bound by ribosomes. The mRNA is read by the ribosome as triplet codons, usually beginning with an AUG, or initiator methonine codon downstream of the ribosome binding site. Complexes of initiation factors and elongation factors bring aminoacylated transfer RNAs (tRNAs) into the ribosome-mRNA complex, matching the codon in the mRNA to the anti-codon in the tRNA, thereby adding the correct amino acid in the sequence encoding the gene. As the amino acids are linked into the growing peptide chain, they begin folding into the correct conformation. This folding continues until the nascent polypeptide chains are released from the ribosome as a mature protein. In some cases the new polypeptide chain requires additional processing to make a mature protein. The correct folding process is quite complex and may require other proteins, called chaperone proteins. Occasionally proteins themselves can be further spliced, when this happens the inside "discarded" section is known as an intein. Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ...
Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ...
Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ...
Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ...
Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...
HeLa cells stained for DNA with the Blue Hoechst dye. ...
It has been suggested that Cytoplast be merged into this article or section. ...
A series of codons in a short RNA molecule. ...
Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ...
Biological and artificial methods for creation of proteins differ significantly. ...
Elongation factors are a set of proteins that facilitate the events of translational elongation, the steps in protein synthesis from the formation of the first peptide bond to the formation of the last one. ...
Aminoacylation is the process of adding an aminoacyl group to a compound. ...
It has been suggested that Queuine be merged into this article or section. ...
Phenylalanine is one of the standard amino acids. ...
A chaperone protein catalyzes the correct folding of other proteins within the cell. ...
An intein is a segment of a protein that is able to excise itself and rejoin the remaining portions (the exteins) with a peptide bond. ...
Special transfers of biological sequential information
Reverse transcription -
Reverse transcription is the transfer of information from RNA to DNA (the reverse of normal transcription). This is known to occur in the case of retroviruses, such as HIV, and, in higher eukaryotes, in the case of retrotransposons. It is not, however, the general case in most living organisms. Reverse transcriptase is an enzyme used by all retroviruses and retrotransposons that transcribes the genetic information from the virus or retrotransposon from RNA into DNA, which can integrate into the host genome. ...
Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is any virus belonging to the viral family Retroviridae. ...
Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ...
Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta Opisthokonta Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ...
Retrotransposons are genetic elements than can amplify themselves in a genome and are ubiquitous components of the DNA of many eukaryotic organisms. ...
RNA replication RNA replication is the copying of one RNA to another. It is possible that this is the mechanism by which some RNA viruses replicate.[2] An RNA virus is a virus that either uses RNA as its genetic material, or whose genetic material passes through an RNA intermediate during replication. ...
Direct translation from DNA to protein This has been shown to occur in a cell-free system (i.e. in a test tube), using neomycin.[2] Neomycin is an aminoglycoside antibiotic that is found in many topical medications such as creams, ointments and eyedrops. ...
Methylation Variation in methylation states of DNA can alter gene expression levels significantly. Methylation variation usually occurs through the action of DNA methylases (which are proteins). When the change is heritable, it is considered epigenetic. When the change in information status is not heritable, it would be a somatic epitype. The effective information content has been changed by means of the actions of a protein or proteins on DNA, but the primary DNA sequence is not altered. Epigenetic inheritance is the transmission of information from a cell or multicellular organism to its descendants without that information being encoded in the nucleotide sequence of the gene. ...
A somatic epitype is a non-heritable epigenetic alteration in a gene. ...
Prions - almost an "unknown transfer" Prions are proteins that propagate themselves by making conformational changes in other molecules of the same type of protein. This change affects the behaviour of the protein. In fungi this change can be passed from one generation to the next, i.e. Protein → Protein. Although this represents a transfer of information, it is not an exception to the central dogma, since the sequence of the protein remains unchanged. A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on) that lacks nucleic acid (by analogy to virion) — is a type of infectious agent composed only of protein. ...
Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ...
Use of the term "dogma" In his autobiography, What Mad Pursuit, Crick wrote about his choice of the word dogma and some of the problems it caused him: Cover of the first English edition of 1793 of Benjamin Franklins autobiography. ...
For the film Dogma, see Dogma (film) Dogma (the plural is either dogmata or dogmas, Greek , plural ) is the established belief or doctrine held by a religion, ideology or any kind of organization, thought to be authoritative and not to be disputed or doubted. ...
- I called this idea the central dogma, for two reasons, I suspect. I had already used the obvious word hypothesis in the sequence hypothesis, and in addition I wanted to suggest that this new assumption was more central and more powerful. ... As it turned out, the use of the word dogma caused almost more trouble than it was worth.... Many years later Jacques Monod pointed out to me that I did not appear to understand the correct use of the word dogma, which is a belief that cannot be doubted. I did apprehend this in a vague sort of way but since I thought that all religious beliefs were without foundation, I used the word the way I myself thought about it, not as most of the world does, and simply applied it to a grand hypothesis that, however plausible, had little direct experimental support.
Look up Hypothesis in Wiktionary, the free dictionary. ...
Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biologist and a Nobel Prize Winner in Physiology or Medicine in 1965. ...
Criticisms of the use of the central dogma as a research strategy Some researchers in the area of systems biology claim that scientists sometimes misuse the central dogma as a research strategy. They claim that an uncritical reading of the central dogma could inhibit novel approaches to understanding multicellular development of organisms as well as multicellular diseases; that the central dogma is often used as a reductionist research strategy that proceeds bottom up, attempting to explain all biological phenomena in molecular terms. Although they don't dispute the very specific reading of the central dogma, these researchers claim that a reductionist research strategy may limit the understanding of complex systems that cannot be analyzed by their molecular interactions alone because of the combinatorial complexity involved.[3] Systems biology is a term used very widely in the biosciences, particularly from the year 2000 onwards, and in a variety of contexts. ...
The term scientific reductionism has been used to describe various reductionist ideas about science. ...
See also Various modes of alternative splicing Alternative splicing is the process that occurs in eukaryotes in which the splicing process of a pre-mRNA transcribed from one gene can lead to different mature mRNA molecules and therefore to different proteins. ...
In molecular biology, a riboswitch is a part of an mRNA molecule that can directly bind a small target molecule, and whose binding of the target affects the genes activity. ...
References - ^ Crick, F.H.C. (1958): On Protein Synthesis. Symp. Soc. Exp. Biol. XII, 139-163. (pdf, early draft of original article)
- ^ a b c d Crick, F. (1970): Central Dogma of Molecular Biology. Nature 227, 561-563. PMID 4913914
- ^ Werner, E. (2005): Genome Semantics, In Silico Multicellular Systems and the Central Dogma. FEBS Letters 579, 1779-1782. PMID 15763551
Further Reading - Lerner, Brenda Wilmoth & K. Lee Lerner (eds) (2006). Medicine, health, and bioethics : essential primary sources, 1st ed., Thomson Gale. ISBN 1414406231.
External links - Central Dogma : Article from MIT Biology Hypertextbook
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