Genetic code - Knowledge (XXG)

433: 2159:) and later incorporated some of these into the machinery of genetic coding. Although much circumstantial evidence has been found to suggest that fewer amino acid types were used in the past, precise and detailed hypotheses about which amino acids entered the code in what order are controversial. However, several studies have suggested that Gly, Ala, Asp, Val, Ser, Pro, Glu, Leu, Thr may belong to a group of early-addition amino acids, whereas Cys, Met, Tyr, Trp, His, Phe may belong to a group of later-addition amino acids. 2024:, GUG and UUG are common start codons. In rare cases, certain proteins may use alternative start codons. Surprisingly, variations in the interpretation of the genetic code exist also in human nuclear-encoded genes: In 2016, researchers studying the translation of malate dehydrogenase found that in about 4% of the mRNAs encoding this enzyme the stop codon is naturally used to encode the amino acids tryptophan and arginine. This type of recoding is induced by a high-readthrough stop codon context and it is referred to as 729: 814:

the first position of the codons are more important than changes in the second position on a global scale. The reason may be that charge reversal (from a positive to a negative charge or vice versa) can only occur upon mutations in the first position of certain codons, but not upon changes in the second position of any codon. Such charge reversal may have dramatic consequences for the structure or function of a protein. This aspect may have been largely underestimated by previous studies.

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universality of the genetic code. However, in his seminal paper on the origins of the genetic code in 1968, Francis Crick still stated that the universality of the genetic code in all organisms was an unproven assumption, and was probably not true in some instances. He predicted that "The code is universal (the same in all organisms) or nearly so". The first variation was discovered in 1979, by researchers studying

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Templates and the Adaptor Hypothesis: A Note for the RNA Tie Club" to the members of the club in January 1955, which "totally changed the way we thought about protein synthesis", as Watson recalled. The hypothesis states that the triplet code was not passed on to amino acids as Gamow thought, but carried by a different molecule, an adaptor, that interacts with amino acids. The adaptor was later identified as tRNA.

9431: 7762: 590: 9455: 8229: 745: 33: 9443: 2035:, ribosomes, single direction reading and translating single codons into single amino acids. The most extreme variations occur in certain ciliates where the meaning of stop codons depends on their position within mRNA. When close to the 3' end they act as terminators while in internal positions they either code for amino acids as in 2166:. A recent hypothesis suggests that the triplet code was derived from codes that used longer than triplet codons (such as quadruplet codons). Longer than triplet decoding would increase codon redundancy and would be more error resistant. This feature could allow accurate decoding absent complex translational machinery such as the 481:" (ORF). For example, the string 5'-AAATGAACG-3' (see figure), if read from the first position, contains the codons AAA, TGA, and ACG ; if read from the second position, it contains the codons AAT and GAA ; and if read from the third position, it contains the codons ATG and AAC. Every sequence can, thus, be read in its 2202:

Stop codons: Codons for translational stops are also an interesting aspect to the problem of the origin of the genetic code. As an example for addressing stop codon evolution, it has been suggested that the stop codons are such that they are most likely to terminate translation early in the case of a

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Given the non-random genetic triplet coding scheme, a tenable hypothesis for the origin of genetic code could address multiple aspects of the codon table, such as absence of codons for D-amino acids, secondary codon patterns for some amino acids, confinement of synonymous positions to third position,

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is in use. The logo shows the 64 codons from left to right, predicted alternatives in red (relative to the standard genetic code). Red line: stop codons. The height of each amino acid in the stack shows how often it is aligned to the codon in homologous protein domains. The stack height indicates the

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Note in the table, below, eight amino acids are not affected at all by mutations at the third position of the codon, whereas in the figure above, a mutation at the second position is likely to cause a radical change in the physicochemical properties of the encoded amino acid. Nevertheless, changes in

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In a broad academic audience, the concept of the evolution of the genetic code from the original and ambiguous genetic code to a well-defined ("frozen") code with the repertoire of 20 (+2) canonical amino acids is widely accepted. However, there are different opinions, concepts, approaches and ideas,

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protein-coding sequences. One reason inheritance of frameshift mutations is rare is that, if the protein being translated is essential for growth under the selective pressures the organism faces, absence of a functional protein may cause death before the organism becomes viable. Frameshift mutations

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combine elements of game theory, natural selection and information channels. Such models have been used to suggest that the first polypeptides were likely short and had non-enzymatic function. Game theoretic models suggested that the organization of RNA strings into cells may have been necessary to

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Stereochemical affinity: the genetic code is a result of a high affinity between each amino acid and its codon or anti-codon; the latter option implies that pre-tRNA molecules matched their corresponding amino acids by this affinity. Later during evolution, this matching was gradually replaced with

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A hypothetical randomly evolved genetic code further motivates a biochemical or evolutionary model for its origin. If amino acids were randomly assigned to triplet codons, there would be 1.5 × 10 possible genetic codes. This number is found by calculating the number of ways that 21 items

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Variant genetic codes used by an organism can be inferred by identifying highly conserved genes encoded in that genome, and comparing its codon usage to the amino acids in homologous proteins of other organisms. For example, the program FACIL infers a genetic code by searching which amino acids in

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approaches model the process of translating the genetic code into corresponding amino acids as an error-prone information channel. The inherent noise (that is, the error) in the channel poses the organism with a fundamental question: how can a genetic code be constructed to withstand noise while

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There was originally a simple and widely accepted argument that the genetic code should be universal: namely, that any variation in the genetic code would be lethal to the organism (although Crick had stated that viruses were an exception). This is known as the "frozen accident" argument for the

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The first scientific contribution of the club, later recorded as "one of the most important unpublished articles in the history of science" and "the most famous unpublished paper in the annals of molecular biology", was made by Crick. Crick presented a type-written paper titled "On Degenerate

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Amino acids that share the same biosynthetic pathway tend to have the same first base in their codons. This could be an evolutionary relic of an early, simpler genetic code with fewer amino acids that later evolved to code a larger set of amino acids. It could also reflect steric and chemical

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models suggest that the genetic code originated as a result of the interplay of the three conflicting evolutionary forces: the needs for diverse amino acids, for error-tolerance and for minimal resource cost. The code emerges at a transition when the mapping of codons to amino acids becomes

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Since 2001, 40 non-natural amino acids have been added into proteins by creating a unique codon (recoding) and a corresponding transfer-RNA:aminoacyl – tRNA-synthetase pair to encode it with diverse physicochemical and biological properties in order to be used as a tool to exploring

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The three stop codons were named by discoverers Richard Epstein and Charles Steinberg. "Amber" was named after their friend Harris Bernstein, whose last name means "amber" in German. The other two stop codons were named "ochre" and "opal" in order to keep the "color names" theme.

792:(UCA, UCG, UCC, UCU, AGU, or AGC) codons (difference in the first, second, or third position). A practical consequence of redundancy is that errors in the third position of the triplet codon cause only a silent mutation or an error that would not affect the protein because the 448:(in black: positions 8,525 to 8,580 in the sequence accession NC_012920). There are three possible reading frames in the 5' → 3' forward direction, starting on the first (+1), second (+2) and third position (+3). For each codon (square brackets), the amino acid is given by the 423:

genome that is refactored (all overlaps expanded), recoded (removing the use of three out of 64 codons completely), and further modified to remove the now unnecessary tRNAs and release factors. It is fully viable and grows 1.6× slower than its wild-type counterpart "MDS42".

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RNA into protein. Unique triplets promoted the binding of specific tRNAs to the ribosome. Leder and Nirenberg were able to determine the sequences of 54 out of 64 codons in their experiments. Khorana, Holley and Nirenberg received the Nobel Prize (1968) for their work.

1983: 489:, each producing a possibly distinct amino acid sequence: in the given example, Lys (K)-Trp (W)-Thr (T), Asn (N)-Glu (E), or Met (M)-Asn (N), respectively (when translating with the vertebrate mitochondrial code). When DNA is double-stranded, six possible 2073:

database. Despite the NCBI already providing 27 translation tables, the authors were able to find new 5 genetic code variations (corroborated by tRNA mutations) and correct several misattributions. Codetta was later used to analyze genetic code change in

2106:(20 amino acids plus one stop) can be placed in 64 bins, wherein each item is used at least once. However, the distribution of codon assignments in the genetic code is nonrandom. In particular, the genetic code clusters certain amino acid assignments. 181:

was the first to give a workable scheme for protein synthesis from DNA. He postulated that sets of three bases (triplets) must be employed to encode the 20 standard amino acids used by living cells to build proteins, which would allow a maximum of

1950:. Selenocysteine came to be seen as the 21st amino acid, and pyrrolysine as the 22nd. Both selenocysteine and pyrrolysine may be present in the same organism. Although the genetic code is normally fixed in an organism, the achaeal prokaryote 2055:

The origins and variation of the genetic code, including the mechanisms behind the evolvability of the genetic code, have been widely studied, and some studies have been done experimentally evolving the genetic code of some organisms.

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is maintained by equivalent substitution of amino acids; for example, a codon of NUN (where N = any nucleotide) tends to code for hydrophobic amino acids. NCN yields amino acid residues that are small in size and moderate in

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properties that had another effect on the codon during its evolution. Amino acids with similar physical properties also tend to have similar codons, reducing the problems caused by point mutations and mistranslations.

577:. Stop codons are also called "termination" or "nonsense" codons. They signal release of the nascent polypeptide from the ribosome because no cognate tRNA has anticodons complementary to these stop signals, allowing a 2068:

As of January 2022, the most complete survey of genetic codes is done by Shulgina and Eddy, who screened 250,000 prokaryotic genomes using their Codetta tool. This tool uses a similar approach to FACIL with a larger

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Although most mutations that change protein sequences are harmful or neutral, some mutations have benefits. These mutations may enable the mutant organism to withstand particular environmental stresses better than

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The Nobel Prize in Physiology or Medicine 1959 was awarded jointly to Severo Ochoa and Arthur Kornberg 'for their discovery of the mechanisms in the biological synthesis of ribonucleic acid and deoxyribonucleic

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The Nobel Prize in Physiology or Medicine 1968 was awarded jointly to Robert W. Holley, Har Gobind Khorana and Marshall W. Nirenberg 'for their interpretation of the genetic code and its function in protein

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respectively. Clinically important missense mutations generally change the properties of the coded amino acid residue among basic, acidic, polar or non-polar states, whereas nonsense mutations result in a

3507:"Scientists Created Bacteria With a Synthetic Genome. Is This Artificial Life? - In a milestone for synthetic biology, colonies of E. coli thrive with DNA constructed from scratch by humans, not nature" 2155:

Biosynthetic expansion. The genetic code grew from a simpler earlier code through a process of "biosynthetic expansion". Primordial life "discovered" new amino acids (for example, as by-products of

809:) of 12 variables (4 nucleotides x 3 positions) yields a remarkable correlation (C = 0.95) for predicting the hydropathicity of the encoded amino acid directly from the triplet nucleotide sequence, 764:(redundancy), neither specifies another amino acid (no ambiguity). The codons encoding one amino acid may differ in any of their three positions. For example, the amino acid leucine is specified by 6728:

Ntountoumi, Chrysa; Vlastaridis, Panayotis; Mossialos, Dimitris; Stathopoulos, Constantinos; Iliopoulos, Ioannis; Promponas, Vasilios; Oliver, Stephen G; Amoutzias, Grigoris D (4 November 2019).

2012:). Because viruses must use the same genetic code as their hosts, modifications to the standard genetic code could interfere with viral protein synthesis or functioning. However, viruses such as 197:

from genes. However, the club could have only 20 permanent members to represent each of the 20 amino acids; and four additional honorary members to represent the four nucleotides of DNA.

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A reading frame is defined by the initial triplet of nucleotides from which translation starts. It sets the frame for a run of successive, non-overlapping codons, which is known as an "

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Dutilh BE, Jurgelenaite R, Szklarczyk R, van Hijum SA, Harhangi HR, Schmid M, de Wild B, Françoijs KJ, Stunnenberg HG, Strous M, Jetten MS, Op den Camp HJ, Huynen MA (July 2011).

617:, especially if they occur within the protein coding sequence of a gene. Error rates are typically 1 error in every 10–100 million bases—due to the "proofreading" ability of 7600: 2152:

showed that some amino acids have a selective chemical affinity for their codons. Experiments showed that of 8 amino acids tested, 6 show some RNA triplet-amino acid association.

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In some proteins, non-standard amino acids are substituted for standard stop codons, depending on associated signal sequences in the messenger RNA. For example, UGA can code for

1996:. Many slight variants were discovered thereafter, including various alternative mitochondrial codes. These minor variants for example involve translation of the codon UGA as 8185: 2065:

homologous protein domains are most often aligned to every codon. The resulting amino acid (or stop codon) probabilities for each codon are displayed in a genetic code logo.

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Chaliotis, Anargyros; Vlastaridis, Panayotis; Mossialos, Dimitris; Ibba, Michael; Becker, Hubert D.; Stathopoulos, Constantinos; Amoutzias, Grigorios D. (17 February 2017).

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In 2016 the first stable semisynthetic organism was created. It was a (single cell) bacterium with two synthetic bases (called X and Y). The bases survived cell division.

2125:-like ribozymes may have had different affinities for amino acids, with codons emerging from another part of the ribozyme that exhibited random variability. Once enough 310:(tRNA), the adapter molecule that facilitates the process of translating RNA into protein. This work was based upon Ochoa's earlier studies, yielding the latter the 407:

In 2017, researchers in South Korea reported that they had engineered a mouse with an extended genetic code that can produce proteins with unnatural amino acids.

8542: 3614: 2098:(RNA enzymes) to proteins as the principal enzymes in cells. In line with the RNA world hypothesis, transfer RNA molecules appear to have evolved before modern 363:

which is the best way to change it experimentally. Even models are proposed that predict "entry points" for synthetic amino acid invasion of the genetic code.

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Neumann H, Wang K, Davis L, Garcia-Alai M, Chin JW (March 2010). "Encoding multiple unnatural amino acids via evolution of a quadruplet-decoding ribosome".

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Degeneracy is the redundancy of the genetic code. This term was given by Bernfield and Nirenberg. The genetic code has redundancy but no ambiguity (see the

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of the University of Cambridge, hypothesied that information flows from DNA and that there is a link between DNA and proteins. Soviet-American physicist

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Despite these differences, all known naturally occurring codes are very similar. The coding mechanism is the same for all organisms: three-base codons,

7798: 3517: 546:(in bacteria, mitochondria, and plastids). Alternative start codons depending on the organism include "GUG" or "UUG"; these codons normally represent 7086:

Tlusty T (September 2010). "A colorful origin for the genetic code: information theory, statistical mechanics and the emergence of molecular codes".

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the small set of only 20 amino acids (instead of a number approaching 64), and the relation of stop codon patterns to amino acid coding patterns.

830:. The codon varies by organism; for example, most common proline codon in E. coli is CCG, whereas in humans this is the least used proline codon. 9297: 8478: 702:

as their genetic material have rapid mutation rates, which can be an advantage, since these viruses thereby evolve rapidly, and thus evade the

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are defined, three in the forward orientation on one strand and three reverse on the opposite strand. Protein-coding frames are defined by a

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Di Giulio M (October 1989). "The extension reached by the minimization of the polarity distances during the evolution of the genetic code".

9146: 7605: 2217: 737: 805:; NAN encodes average size hydrophilic residues. The genetic code is so well-structured for hydropathicity that a mathematical analysis ( 7449: 4369:

Füllen G, Youvan DC (1994). "Genetic Algorithms and Recursive Ensemble Mutagenesis in Protein Engineering". Complexity International 1.

9286: 8171: 7850: 7830: 7620: 7414: 6410:"Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code" 8535: 7938: 7305: 3976: 3959: 3143: 2427: 2563: 3726: 7272: 6226:

Brown, Sean M.; Voráček, Václav; Freeland, Stephen (5 April 2023). "What Would an Alien Amino Acid Alphabet Look Like and Why?".

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Kubyshkin, V.; Budisa, N. (2017). "Synthetic alienation of microbial organisms by using genetic code engineering: Why and how?".

223: 119:. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of 9101: 8092: 8036: 4143: 2199:

prevent "deceptive" use of the genetic code, i.e. preventing the ancient equivalent of viruses from overwhelming the RNA world.

2094:. Under this hypothesis, any model for the emergence of the genetic code is intimately related to a model of the transfer from 4486: 9220: 8031: 5733:"Mathematica function for # possible arrangements of items in bins? – Online Technical Discussion Groups—Wolfram Community" 3960:"Two novel frameshift mutations causing premature stop codons in a patient with the severe form of Maroteaux-Lamy syndrome" 9503: 8119: 8050: 7791: 6898:

Tlusty T (November 2007). "A model for the emergence of the genetic code as a transition in a noisy information channel".

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Axes 1, 2, 3 are the first, second, and third positions in the codon. The 20 amino acids and stop codons (X) are shown in

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at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries.

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organisms, or reproduce more quickly. In these cases a mutation will tend to become more common in a population through

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can expand its genetic code from 20 to 21 amino acids (by including pyrrolysine) under different conditions of growth.

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Sella G, Ardell DH (September 2006). "The coevolution of genes and genetic codes: Crick's frozen accident revisited".

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Optimality: the genetic code continued to evolve after its initial creation, so that the current code maximizes some

2791:"The dependence of cell-free protein synthesis in E. coli upon naturally occurring or synthetic polyribonucleotides" 2242:

Turanov AA, Lobanov AV, Fomenko DE, Morrison HG, Sogin ML, Klobutcher LA, Hatfield DL, Gladyshev VN (January 2009).

9498: 9242: 9131: 8070: 7454: 7251: 6730:"Low complexity regions in the proteins of prokaryotes perform important functional roles and are highly conserved" 4224:

Holland J, Spindler K, Horodyski F, Grabau E, Nichol S, VandePol S (March 1982). "Rapid evolution of RNA genomes".

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Three main hypotheses address the origin of the genetic code. Many models belong to one of them or to a hybrid:

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to be read, which truncates the protein. These mutations may impair the protein's function and are thus rare in

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Tlusty T (February 2008). "Rate-distortion scenario for the emergence and evolution of noisy molecular codes".

6117:"Origin of the genetic code: a testable hypothesis based on tRNA structure, sequence, and kinetic proofreading" 1952: 1932: 757: 217: 97: 9447: 2207:

error. In contrast, some stereochemical molecular models explain the origin of stop codons as "unassignable".

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were coded for, any major random change in the genetic code would have been lethal; hence it became "frozen".

667:. These mutations usually result in a completely different translation from the original, and likely cause a 9411: 9275: 9176: 8646: 8075: 7892: 7877: 5180:"Novel Ciliate Genetic Code Variants Including the Reassignment of All Three Stop Codons to Sense Codons in 3506: 2593:"Crick's Adaptor Hypothesis and the Discovery of Transfer RNA: Experiment Surpassing Theoretical Prediction" 2090:, according to one version of which self-replicating RNA molecules preceded life as we know it. This is the 325:

revealed the code's triplet nature and deciphered its codons. In these experiments, various combinations of

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Lobanov AV, Heaphy SM, Turanov AA, Gerashchenko MV, Pucciarelli S, Devaraj RR, et al. (January 2017).

9310: 9191: 9141: 8685: 8488: 8080: 8005: 7897: 7407: 6278: 2179: 357: 210: 4980:"The functional readthrough extension of malate dehydrogenase reveals a modification of the genetic code" 679: 9435: 9186: 9038: 9016: 8959: 8690: 8611: 8566: 8483: 8473: 7995: 7980: 7860: 7742: 7576: 7541: 7198:"The genetic code is nearly optimal for allowing additional information within protein-coding sequences" 6788:

Freeland SJ, Wu T, Keulmann N (October 2003). "The case for an error minimizing standard genetic code".

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Sengupta S, Higgs PG (June 2015). "Pathways of Genetic Code Evolution in Ancient and Modern Organisms".

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species, and translation of CUG as a serine rather than leucine in yeasts of the "CTG clade" (such as

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Reading frames in the DNA sequence of a region of the human mitochondrial genome coding for the genes

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amino acids. He named this DNA–protein interaction (the original genetic code) as the "diamond code".

9264: 9106: 9086: 8675: 8586: 8493: 8102: 8000: 7918: 7641: 7459: 7328: 7105: 7044: 6993: 6917: 6852: 6797: 6621: 6513: 6458: 6366: 6235: 6190: 6128: 5984: 5918: 5907:"Role of minimization of chemical distances between amino acids in the evolution of the genetic code" 5863: 5820: 5769: 5653: 5342: 5142: 4883: 4655: 4539: 4233: 4178: 4096: 4016: 3871: 3554: 3457: 3398: 3005: 2920: 2861: 2802: 2304: 2188: 2091: 2043: 237: 174: 116: 3660:"Generation of protein isoform diversity by alternative initiation of translation at non-AUG codons" 776:(UUA, UUG, CUU, CUC, CUA, or CUG) codons (difference in the first or third position indicated using 9121: 8653: 8596: 8591: 8297: 7928: 7721: 7711: 7671: 7571: 7551: 7444: 7439: 6600:"A Thermodynamic Basis for Prebiotic Amino Acid Synthesis and the Nature of the First Genetic Code" 6357:

Sengupta S, Higgs PG (2015). "Pathways of genetic code evolution in ancient and modern organisms".

4772:"A fungal phylogeny based on 42 complete genomes derived from supertree and combined gene analysis" 711: 664: 636: 9454: 4705: 3740: 9071: 8774: 8758: 8733: 8728: 8665: 8606: 8244: 8063: 7946: 7681: 7566: 7561: 7536: 7129: 7095: 7068: 7017: 6983: 6941: 6907: 6821: 6653: 6611: 6560: 6482: 6449:

Amirnovin R (May 1997). "An analysis of the metabolic theory of the origin of the genetic code".

6390: 6259: 6097: 5887: 5793: 5452: 5409: 5366: 4752: 4679: 4421: 4040: 3989: 3588: 3512: 2771: 2622: 2488: 2480: 2336: 2174: 543: 478: 299: 233: 156: 4269:"Clonal interference and the periodic selection of new beneficial mutations in Escherichia coli" 2592: 2162:

Natural selection has led to codon assignments of the genetic code that minimize the effects of

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residues (UGG codons) with unnatural thienopyrrole-alanine in the genetic code of the bacterium

7149:"What can information-asymmetric games tell us about the context of Crick's 'frozen accident'?" 9488: 9386: 9166: 9161: 9156: 9091: 8856: 8743: 8631: 8601: 8508: 8330: 8147: 7765: 7696: 7686: 7676: 7510: 7400: 7356: 7301: 7278: 7257: 7227: 7178: 7121: 7060: 7009: 6933: 6880: 6813: 6767: 6749: 6710: 6692: 6645: 6637: 6580: 6541: 6474: 6431: 6382: 6339: 6298: 6251: 6208: 6156: 6089: 6054: 6010: 5946: 5879: 5836: 5785: 5712: 5681: 5622: 5573: 5522: 5505:

Chin JW (February 2014). "Expanding and reprogramming the genetic code of cells and animals".

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Xie J, Schultz PG (August 2006). "A chemical toolkit for proteins--an expanded genetic code".

5358: 5315: 5266: 5213: 5160: 5111: 5060: 5009: 4960: 4909: 4852: 4803: 4744: 4671: 4619: 4567: 4508: 4413: 4350: 4323: 4298: 4249: 4206: 4124: 4063: 4032: 3981: 3940: 3899: 3840: 3799: 3748: 3681: 3638: 3580: 3483: 3426: 3340: 3285: 3279: 3260: 3211: 3176: 3139: 3108: 3033: 2948: 2889: 2830: 2763: 2722: 2683: 2673: 2614: 2545: 2527: 2472: 2433: 2423: 2393: 2375: 2328: 2320: 2273: 2137: 691: 628: 624: 535: 524:. The start codon alone is not sufficient to begin the process. Nearby sequences such as the 420: 368: 48:. The nucleotides are abbreviated with the letters A, U, G and C. This is mRNA, which uses U ( 4085:"Prevalence of positive selection among nearly neutral amino acid replacements in Drosophila" 2415: 538:

are also required to start translation. The most common start codon is AUG, which is read as

193:, as suggested by Watson, for scientists of different persuasions who were interested in how 9459: 9332: 9151: 9126: 8641: 7726: 7701: 7346: 7336: 7217: 7209: 7168: 7160: 7113: 7052: 7001: 6925: 6870: 6860: 6805: 6757: 6741: 6700: 6684: 6629: 6572: 6531: 6521: 6466: 6421: 6374: 6329: 6290: 6243: 6198: 6146: 6136: 6081: 6044: 6000: 5992: 5936: 5926: 5871: 5828: 5777: 5671: 5661: 5612: 5604: 5563: 5553: 5514: 5479: 5436: 5393: 5350: 5305: 5297: 5256: 5248: 5203: 5195: 5150: 5101: 5091: 5050: 5040: 4999: 4991: 4950: 4940: 4899: 4891: 4842: 4834: 4793: 4783: 4736: 4663: 4609: 4601: 4557: 4547: 4498: 4403: 4395: 4288: 4280: 4241: 4196: 4186: 4114: 4104: 4024: 3971: 3930: 3889: 3879: 3830: 3789: 3781: 3671: 3570: 3562: 3545: 3505: 3473: 3465: 3416: 3406: 3330: 3322: 3250: 3242: 3203: 3168: 3131: 3098: 3090: 3023: 3013: 2938: 2928: 2879: 2869: 2820: 2810: 2753: 2714: 2604: 2535: 2519: 2464: 2383: 2367: 2312: 2263: 2255: 2008: 823: 723: 660: 530: 415: 375: 303: 241: 4646:

Barrell BG, Bankier AT, Drouin J (1979). "A different genetic code in human mitochondria".

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Nirenberg M, Leder P, Bernfield M, Brimacombe R, Trupin J, Rottman F, O'Neal C (May 1965).

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defensive responses. In large populations of asexually reproducing organisms, for example,

554:, respectively, but as start codons they are translated as methionine or formylmethionine. 9321: 9196: 8124: 7961: 7807: 7586: 6426: 6409: 6049: 6032: 5518: 5483: 3306: 602: 386: 127:). That scheme is often referred to as the canonical or standard genetic code, or simply 7332: 7109: 7048: 6997: 6921: 6856: 6801: 6625: 6517: 6462: 6370: 6239: 6194: 6132: 5988: 5922: 5867: 5824: 5773: 5657: 5346: 5146: 5029:"Peroxisomal lactate dehydrogenase is generated by translational readthrough in mammals" 4887: 4727:

Jukes TH, Osawa S (December 1990). "The genetic code in mitochondria and chloroplasts".

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Zhang Y, Lamb BM, Feldman AW, Zhou AX, Lavergne T, Li L, Romesberg FE (February 2017).

3335: 3310: 3255: 3230: 3103: 3078: 2540: 2388: 2355: 2268: 2243: 2195: 2148:

Chemical principles govern specific RNA interaction with amino acids. Experiments with

2087: 1943: 802: 797: 793: 760:

below for the full correlation). For example, although codons GAA and GAG both specify

733: 656: 632: 618: 606: 578: 525: 490: 486: 482: 390: 69: 8163: 6599: 6334: 6317: 6294: 6151: 6116: 5941: 5906: 4847: 4822: 3894: 3859: 3794: 3769: 3676: 3659: 3387:"A semisynthetic organism engineered for the stable expansion of the genetic alphabet" 3028: 2993: 2943: 2908: 2884: 2849: 2825: 2790: 27:

Rules by which information encoded within genetic material is translated into proteins

9477: 9181: 9052: 8993: 8976: 8971: 8929: 8916: 8503: 8424: 8418: 8320: 8152: 7839: 7294: 6536: 6501: 6263: 6085: 5832: 5702: 5676: 5641: 5155: 5130: 4201: 4166: 3592: 2626: 2492: 2411: 1975: 761: 703: 257: 166: 136: 101: 37: 7021: 6945: 6825: 6486: 6394: 5891: 5797: 5456: 5413: 5370: 4756: 4605: 4425: 4399: 4151: 4044: 3993: 2775: 9406: 9096: 8821: 8700: 8695: 8658: 8636: 8621: 8551: 8026: 7956: 7546: 7133: 7072: 7005: 6657: 6101: 5732: 4683: 3609: 3246: 3194:

Xie J, Schultz PG (December 2005). "Adding amino acids to the genetic repertoire".

2340: 2222: 2037: 2032: 918: 898: 878: 858: 826:, can vary from species to species with functional implications for the control of 322: 307: 264: 190: 178: 170: 124: 105: 4526:

Prat L, Heinemann IU, Aerni HR, Rinehart J, O'Donoghue P, Söll D (December 2012).

2848:

Gardner RS, Wahba AJ, Basilio C, Miller RS, Lengyel P, Speyer JF (December 1962).

468:

gene starts with the ATG codon (blue circle for the M amino acid) in the +3 frame.

260:. They thereby deduced that the codon UUU specified the amino acid phenylalanine. 6865: 6576: 5706: 5096: 4344: 4317: 3935: 3918: 3835: 3818: 3632: 3094: 2994:"RNA codewords and protein synthesis, VII. On the general nature of the RNA code" 2907:

Wahba AJ, Gardner RS, Basilio C, Miller RS, Speyer JF, Lengyel P (January 1963).

2667: 2642:"On Degenerate Templates and the Adaptor Hypothesis: A Note for the RNA Tie Club" 9396: 9033: 9011: 9006: 9001: 8981: 8954: 8949: 8900: 8871: 8831: 8811: 8789: 8462: 8395: 8129: 8058: 7646: 7117: 5760:

Freeland SJ, Hurst LD (September 1998). "The genetic code is one in a million".

4823:"The CUG codon is decoded in vivo as serine and not leucine in Candida albicans" 4284: 3501: 2523: 2204: 1947: 640: 589: 521: 494: 253: 8228: 7321: