[Late reperfusion in acute myocardial infarct. The importance of the open infarct vessel].
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Coronary Vessels↗
Biomedical subjects
C J Michel
Publications and source records attributed to C J Michel.
An evolutionary model of a complementary circular code.
The subset X0 = [sequence: see text] of 20 trinucleotides has a preferential occurrence in frame 0 (a reading frame established by the ATG start trinucleotide) of protein (coding) genes of both prokaryotes and eukaryotes. This subset X0++ has the rarity property (6 x 10(-8)) to be a complementary maximal circular code with two permutated maximal circular codes X1 and X2 in frames 1 and 2 respectively (frame 0 shifted by one and two nucleotides respectively in the 5'-3' direction). X0 is called a C3 code. A quantitative study of these three subsets X0, X1 and X2 in the three frames 0, 1 and 2 of eukaryotic protein genes shows that their occurrence frequencies are constant functions of the trinucleotide positions in the sequences. The frequencies of X0, X1 and X2 in frame 0 of the eukaryotic protein genes are 48.5%, 29% and 22.5% respectively. These properties are not observed in the 5' and 3' regions of eukaryotes where X0, X1 and X2 occur with variable frequencies around the random value (1/3). Several frequency asymmetries unexpectedly observed, e.g. the frequency difference between X1 and X2 in the frame 0, are related to a new property of the C3 code X0 involving substitutions. An evolutionary model at three parameters (p, q, k) based on an independent mixing of the 20 codons (trinucleotides in frame 0) of X0 with equiprobability (1/20) followed by k approximately 5 substitutions per codon in the three codon sites in proportions p approximately 0.1, q approximately 0.1 and r = 1-p-q approximately 0.8 respectively, retrieves the frequencies of X0, X1 and X2 observed in the three frames of protein genes and explains these asymmetries.
Animals↗
[Intracoronary dipyridamole reduces the incidence of acute coronary vessel occlusion in percutaneous transluminal coronary angioplasty--a prospective randomized study].
Even in the era of coronary stenting, acute coronary artery occlusion continues to represent a significant limitation of percutaneous transluminal coronary angioplasty (PTCA). Despite application of heparin and aspirin, abrupt vessel closure still occurs in 2-8%, depending on the definition applied. Especially patients receiving PTCA for acute coronary syndromes are at high risk for abrupt vessel closure. The formation of an intracoronary thrombus plays a central role in the pathogenesis of abrupt vessel closure. Dipyridamole induces dilatation of coronary arteries and prevents platelet aggregation by a mechanism that differs from that of aspirin. The primary purpose of the study was to evaluate whether adjunctive local intracoronary therapy with dipyridamole could reduce the incidence of coronary artery occlusion following PTCA. Secondary endpoints were defined as myocardial infarction, necessity for bypass grafting, and death. In 939 PTCA procedures performed for stable angina and in 155 angioplasty procedures for acute coronary syndromes (unstable angina, acute myocardial infarction), patients were randomized to receive conventional pretreatment consisting of heparin 15,000 I.E. and aspirin 500 mg i.v. or additional intracoronary infusion of dipyridamole (0.5 mg/kg body weight). Dipyridamole was applied in 550 interventions (455 interventions in men, 95 interventions in women, age = 59.2 +/- 8.4; 74 emergency procedures); conventional pretreatment was performed in 544 interventions (444 interventions in men, 100 interventions in women, age 58.3 +/- 7.9; 81 emergency procedures). Intracoronary application of dipyridamole resulted in a significant reduction in the incidence of abrupt vessel closure following PTCA. This significant reduction was observed in patients presenting with stable ischemia as well as in patients receiving PTCA for acute coronary syndromes. Concerning secondary end points, intracoronary application of dipyridamole did not affect the need for bypass grafting or the incidence of death following PTCA. Intracoronary application of dipyridamole was associated with a reduction in the incidence of myocardial infarction following PTCA which, however, failed to reach significance.
Adult↗
[Acute coronary vessel occlusion after PTCA--possibility of risk stratification using quantitative coronary angiography, clinical determinants and laboratory chemistry parameters].
Abrupt vessel closure of the dilated vessel continues to represent a significant limitation of coronary angioplasty. Despite increasing operator experience and improved technology, abrupt vessel closure continues to represent the most important complication of balloon angioplasty. Intracoronary stent implantation and pharmaceutical blockade of the GPIIb/IIIa receptor serve as effective tools in the prevention of abrupt vessel closure without completely resolving this problem. About 50% of patients presenting with abrupt vessel closure exhibit additional complications including myocardial infarction, necessity of CABG or death occurring in up to 10% of acute occlusions. The purpose of this study is to evaluate if quantitative coronary angiography and assessment of clinical and laboratory data allows risk stratification concerning the probability of abrupt vessel closure. PTCA in the setting of acute coronary syndrome is associated with a markedly increased risk of abrupt vessel closure, indicating that different risk factors may contribute to the development of abrupt vessel closure in patients presenting with stable angina or acute coronary insufficiency syndromes. 798 uncomplicated PTCA procedures for stable angina pectoris were compared with 68 interventions that were complicated by abrupt vessel closure. Furthermore, 133 successful angioplasty procedures for acute coronary syndromes defined as acute myocardial infarction or unstable angina pectoris were matched with 31 procedures for acute coronary syndromes with consecutive abrupt vessel closure. In patients presenting with stable angina pectoris stenosis length, stenosis eccentricity, minimal lumen diameter, degree of the stenosis after angioplasty, female gender, and fibrinogen could be defined as independent predictors of abrupt vessel closure. In acute coronary syndromes, only minimal lumen diameter, recanalization of completely occluded coronary arteries and fibrinogen were associated with an increased risk of abrupt vessel closure.
Aged↗
A code in the protein coding genes.
A statistical analysis with 12,288 autocorrelation functions applied in protein (coding) genes of prokaryotes and eukaryotes identifies three subsets of trinucleotides in their three frames: T0 = X0 [symbol: see text] {AAA, TTT} with X0 = {AAC, AAT, ACC, ATC, ATT, CAG, CTC, CTG, GAA, GAC, GAG, GAT, GCC, GGC, GGT, GTA, GTC, GTT, TAC, TTC} in frame 0 (the reading frame established by the ATG start trinucleotide), T1 = X1 [symbol: see text] {CCC} in frame 1 and T2 = X2 [symbol: see text] {GGG} in frame 2 (the frames 1 and 2 being the frame 0 shifted by one and two nucleotides, respectively, to the right). These three subsets are identical in these two gene populations and have five important properties: (i) the property of maximal (20 trinucleotides) circular code for X0 (resp. X1, X2) allowing to retrieve automatically the frame 0 (resp. 1, 2) in any region of the gene without start codon; (ii) the DNA complementarity property C (e.g. C(AAC) = GTT): C(T0) = T0, C(T1) = T2 and C(T2) = T1 allowing the two paired reading frames of a DNA double helix simultaneously to code for amino acids; (iii) the circular permutation property P (e.g. P(AAC) = ACA): P(X0) = X1 and P(X1) = X2 implying that the two subsets X1 and X2 can be deduced from X0; (iv) the rarity property with an occurrence probability of X0 = 6 x 10(-8); and (v) the concatenation properties in favour of an evolutionary code: a high frequency (27.5%) of misplaced trinucleotides in the shifted frames, a maximum (13 nucleotides) length of the minimal window to retrieve automatically the frame and an occurrence of the four types of nucleotides in the three trinucleotide sites. In Discussion, a simulation based on an independent mixing of the trinucleotides of T0 allows to retrieve the two subsets T1 and T2. Then, the identified subsets T0, T1 and T2 replaced in the 2-letter genetic alphabet {R, Y} (R = purine = A or G, Y = pyrimidine = C or T) allow to retrieve the RNY model (N = R or Y) and to explain previous works in the alphabet {R, Y}. Then, these three subsets are related to the genetic code. The trinucleotides of T0 code for 13 amino acids: Ala, Asn, Asp, Gln, Glu, Gly, Ile, Leu, Lys, Phe, Thr, Tyr and Val. Finally, a strong correlation between the usage of the trinucleotides of T0 in protein genes and the amino acid frequencies in proteins is observed as six among seven amino acids not coded by T0, have as expected the lowest frequencies in proteins of both prokaryotes and eukaryotes.
Animals↗
[Interventional therapy in acute myocardial infarct].
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Angioplasty, Balloon, Coronary↗
[Indications and limits of conventional revascularization methods in coronary heart disease].
The number of cardiologic patients undergoing invasive diagnostic catheterization is rapidly increasing. Due to more liberal and extensive indications for invasive diagnosis patients in relatively unfavorable clinical condition (e.g., elderly patients with severe extracardial disease, patients status post CABG) are being catheterized and, if suitable and indicated, undergo revascularization procedures. With rapidly increasing procedural skill of cardiovascular surgeons and invasive cardiologists even high-risk patients with severe coronary artery disease or underlying illness, who were classically excluded from surgical or catheter-invasive revascularization, are now being treated more aggressively. The changing indications for diagnostic catheterization and significant changes in the different modes of revascularization--operative bypass-surgery or interventional procedures--have led to continuous changes in the differential indications for these invasive therapeutic strategies. This article reviews and discusses the currently accepted indications for surgical and interventional revascularization as well as the limitations of these procedures.
Adult↗
A complementary circular code in the protein coding genes.
Recently, shifted periodicities 1 modulo 3 and 2 modulo 3 have been identified in protein (coding) genes of both prokaryotes and eukaryotes with autocorrelation functions analysing eight of 64 trinucleotides (Arquès et al., 1995). This observation suggests that the trinucleotides are associated with frames in protein genes. In order to verify this hypothesis, a distribution of the 64 trinucleotides AAA,..., TTT is studied in both gene populations by using a simple method based on the trinucleotide frequencies per frame. In protein genes, the trinucleotides can be read in three frames: the reading frame 0 established by the ATG start trinucleotide and frame 1 (resp. 2) which is the frame 0 shifted by 1 (resp. 2) nucleotide in the 5'-3' direction. Then, the occurrence frequencies of the 64 trinucleotides are computed in the three frames. By classifying each of the 64 trinucleotides in its preferential occurrence frame, i.e. the frame associated with its highest frequency, three subsets of trinucleotides can be identified in the three frames. This approach is applied in the two gene populations. Unexpectedly, the same three subsets of trinucleotides are identified in these two gene populations: Tzero = Xzero [symbol: see text] {AAA,TTT} with Xzero = {AAC,AAT,ACC,ATC,ATT, CAG,CTC,CTG,GAA,GAC,GAG, GAT,GCC,GGC,GGT,GTA,GTC,GTT,TAC,TTC} in frame 0, T1 = X1 [symbol: see text] {CCC} in frame 1 and T2 = X2 [symbol: see text] {GGG} in frame 2, each subset Xzero, X1 and X2 having 20 trinucleotides. Surprisingly, these three subsets have five important properties: (i) the property of maximal circular code for Xzero (resp. X1, X2) allowing the automatical retrieval of frame 0 (resp. 1, 2) in any region of a protein gene model (formed by a series of trinucleotides of Xzero) without using a start codon; (ii) the DNA complementarity property C (e.g. C(AAC) = GTT): C(T0) = T0, C(T1) = T2 and C(T2) = T1 allowing the two paired reading frames of a DNA double helix simultaneously to code for amino acids; (iii) the circular permutation property P (e.g. P(AAC) = ACA): P(Xzero) = X1 and P(X1) = X2 implying that the two subsets X1 and X2 can be deduced from Xzero; (iv) the rarity property with an occurrence probability of Xzero equal to 6 x 10(-8); and (v) the concatenation property with: a high frequency (27.5%) of misplaced trinucleotides in the shifted frames, a maximum (13 nucleotides) length of the minimal window to automatically retrieve the frame and an occurrence of the four types of nucleotides in the three trinucleotides sites, in favour of an evolutionary code. In the Discussion, the identified subsets Tzero, T1 and T2 replaced in the three two-letter genetic alphabets purine/pyrimidine, amino/ceto and strong/weak interaction, allow us to deduce that the RNY model (R = purine = A or G, Y = pyrimidine = C or T, N = R or Y) (Eigen & Schuster, 1978) is the closest two-letter codon model to the trinucleotides of Tzero. Then, these three subsets are related to the genetic code. The trinucleotides of Tzero code for 13 amino acids: Ala, Asn, Asp, Gln, Glu, Gly, Ile, Leu, Lys, Phe, Thr, Tyr and Val. Finally, a strong correlation between the usage of the trinucleotides of Tzero in protein genes and the amino acid frequencies in proteins is observed as six among seven amino acids not coded by Tzero, have as expected the lowest frequencies in proteins of both prokaryotes and eukaryotes.
Amino Acids↗
Identification of several types of periodicities in the collagens and their simulation.
The collagens constitute an important population of proteins providing the structural support in vertebrate tissues A collagen is mainly based on a series of tripeptides of the type GX1X2 (G = Glycine, X1 and X2 being any residues). The nine amino acids occurring with significant frequencies in the X1 and X2 residue sites and G form the reduced protein alphabet Q = [A,D,E,G,K,L,P,Q,R,S] (A = Alanine, D = Aspartic acid, E = Glutamic acid, K = Lysine, L = Leucine, P = Proline, Q = Glutamine, R = Arginine, S = Serine). Surprisingly, the method based on the autocorrelation function w(X)iw' analysing the probability that an amino acid w' in Q occurs any i residues X after an amino acid w in Q (called i-motif w(X)iw'), identifies six types of modulo 3 periodicities in collagens: three basic types 0, 1 and 2 modulo 3 and three combined types 0,1, 0,2 and 1,2 modulo 3. Furthermore, the classification of these 100 i-motifs according to the types of periodicities shows several strong relations between four sub-sets of Q [G], [A,D,P,S], [E,L] and [K,Q,R]. Then, these relations allow the construction of a simple automaton for the generation of model collagen sequences. Indeed, this automaton can simulate the six types of periodicities and it retrieves the types of periodicities for almost all i-motifs. Finally, the autocorrelation function based on the sub-set [K,Q,R] identifies segments of 18 amino acids in collagens which may correspond to the exons (segments of genes of 54 nucleotides) coding for those collagens.
Algorithms↗
[Thrombolysis in acute myocardial infarct].
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Angioplasty, Balloon, Coronary↗
Analytical solutions of the dinucleotide probability after and before random mutations.
The mutation process is a classical evolutionary genetic process mainly based on the (random) substitutions of one base (A = Adenine, C = Cytosine, G = Guanine, T = Thymine) for another. Two analytical solutions derived here allow us to analyse in genes the occurrence probabilities of motifs (e.g. dinucleotides) after substitutions (in the evolutionary sense: from the past to the present) and, unexpectedly, also before substitutions (after back substitutions, in the inverse evolutionary sense: from the present to the past). We generalize on the alphabet [A, C, G, T] of the analytical solutions and of the properties derived on the alphabet [R, Y] (R = purine = A or G, Y = pyrimidine = C or T). Application of the theory is based on the analytical solution giving the probabilities of the 16 dinucleotides AA, ..., TT in the protein (coding) genes of (nuclear) eukaryotes, viruses and prokaryotes and in (eukaryotic) introns after back substitutions (called primitive genes). After back substitutions, four of 16 dinucleotides--CG, TA, GT and AC--occur with low probabilities in each of these four primitive gene populations, except for CG in the primitive prokaryotic protein genes. In the primitive eukaryotic protein genes, the dinucleotide AT has also a significant low probability. We present the properties of the two analytical solutions, and the functions which may have these five dinucleotides in primitive genes are described in terms of biological signals.
Animals↗
Identification and simulation of shifted periodicities common to protein coding genes of eukaryotes, prokaryotes and viruses.
The distribution of nucleotides in protein coding genes is studied with autocorrelation functions. The autocorrelation function YRY(N)iYRY, analysing the occurrence probability of the i-motif YRY(N)iYRY (two motifs YRY separated by any i bases N, R = purine = Adenine or Guanine, Y = pyrimidine = Cytosine or Thymine, N = R or Y) in the protein coding genes of eukaryotes, prokaryotes and viruses, reveals the classical periodicity 0 modulo 3 associated with the normal frame 0 (maximal values of the function at i = 0, 3, 6, etc). The specification of YRY(N)iYRY on the alphabet [A, C, G, T] leads to 64 i-motifs: CAC(N)iCAC, CAC(N)iCAT, ..., TGF(N)iTGT. The 64 autocorrelation functions associated with these 64 i-motifs in protein coding genes have all the periodicity modulo 3, but, surprisingly, not always the expected periodicity 0 modulo 3. Two new types of periodicities are identified: a periodicity 1 modulo 3 associated with the shifted frame +1 (maximal values of the function at i = 1, 4, 7, etc) and a periodicity 2 modulo 3 associated with the shifted frame -1 (maximal values of the function at i = 2, 5, 8 etc). Furthermore, the classification of i-motifs according to the type of periodicity demonstrates a strong coherence relation between the 64 i-motifs, which is, in addition, common to the three gene populations, as the same i-motifs in the three gene populations have the same periodicities. The three periodicities 0, 1 and 2 modulo 3 can be simulated by an evolutionary model at two successive processes. The simulated genes are generated by a process of gene construction, with a stochastic automaton followed by a process of gene evolution with random insertions and deletions of trinucleotides simulating RNA editing. For almost all i-motifs, the autocorrelation functions in these simulated genes are strongly correlated with those in protein coding genes, for both the type and the probability level of periodicities. This paper describes the process of ribosomal frameshifting leading to the shifted periodicities, which may reveal overlapping genes or concatenated genes from different frames. It also presents the evolutionary aspects of the shifted periodicities. The shifted periodicities cannot be associated with the RNY model (Eigen & Schuster, 1978, Naturwissenschaften 65, 341-369) or the RRY model (Crick et al., 1976, Origins of Life 7, 389-397), but are compatible with the oligonucleotide mixing model (Arquès & Michel, 1990, Bull. math. Biol. 52, 741-772). Finally, a variant of the primitive translation model of Crick et al. (1976) is proposed to explain the shifted periodicities.
Animals↗
Analytical expression of the purine/pyrimidine autocorrelation function after and before random mutations.
The mutation process is a classical evolutionary genetic process. The type of mutations studied here is the random substitutions of a purine base R (adenine or guanine) by a pyrimidine base Y (cytosine or thymine) and reciprocally (transversions). The analytical expressions derived allow us to analyze in genes the occurrence probabilities of motifs and d-motifs (two motifs separated by any d bases) on the R/Y alphabet under transversions. These motif probabilities can be obtained after transversions (in the evolutionary sense; from the past to the present) and, unexpectedly, also before transversions (after back transversions, in the inverse evolutionary sense, from the present to the past). This theoretical part in Section 2 is a first generalization of a particular formula recently derived. The application in Section 3 is based on the analytical expression giving the autocorrelation function (the d-motif probabilities) before transversions. It allows us to study primitive genes from actual genes. This approach solves a biological problem. The protein coding genes of chloroplasts and mitochondria have a preferential occurrence of the 6-motif YRY(N)6YRY (maximum of the autocorrelation function for d = 6, N = R or Y) with a periodicity modulo 3. The YRY(N)6YRY preferential occurrence without the periodicity modulo 3 is also observed in the RNA coding genes (ribosomal, transfer, and small nuclear RNA genes) and in the noncoding genes (introns and 5' regions of eukaryotic nuclei). However, there are two exceptions to this YRY(N)6YRY rule: the protein coding genes of eukaryotic nuclei, and prokaryotes, where YRY(N)6YRY has the second highest value after YRY(N)0YRY (YRYYRY) with a periodicity modulo 3. When we go backward in time with the analytical expression, the protein coding genes of both eukaryotic nuclei and prokaryotes retrieve the YRY(N)6YRY preferential occurrence with a periodicity modulo 3 after 0.2 back transversions per base. In other words, the actual protein coding genes of chloroplasts and mitochondria are similar to the primitive protein coding genes of eukaryotic nuclei and prokaryotes. On the other hand, this application represents the first result concerning the mutation process in the model of DNA sequence evolution we recently proposed. According to this model, the actual genes on the R/Y alphabet derive from two successive evolutionary genetic processes: an independent mixing of a few nonrandom types of oligonucleotides leading to genes called primitive followed by a mutation process in these primitive genes.(ABSTRACT TRUNCATED AT 400 WORDS)
Base Sequence↗
Brain glucose utilization in band heterotopia: synaptic activity of "double cortex".
Regional brain glucose utilization was investigated with positron emission tomography and fluorodeoxyglucose in 2 patients with a seizure disorder associated with diffuse band heterotopia, a condition known as "double cortex." Although 1 patient was examined shortly after the onset of the first seizures, the other had a long history of intractable epilepsy before examination. Magnetic resonance imaging revealed a symmetric and generalized band of ectopic gray matter and an overlying normal-looking cortex, without focal abnormality. Metabolic studies yielded comparable results in both patients, with similar and even higher glucose uptake in the layer of gray matter heterotopia compared to the normal cortex. These data suggest the persistence of some synaptic activity in the heterotopic neurons, which seems unaffected by age or by the time-course of epilepsy.
Adult↗
Identification and simulation of new non-random statistical properties common to different populations of eukaryotic non-coding genes.
The autocorrelation function analysing the occurrence probability of the i-motif YRY(N)iYRY in genes allows the identification of mainly two periodicities modulo 2, 3 and the preferential occurrence of the motif YRY(N)6YRY (R = purine = adenine or guanine, Y = pyrimidine = cytosine or thymine, N = R or Y). These non-random genetic statistical properties can be simulated by an independent mixing of the three oligonucleotides YRYRYR, YRYYRY and YRY(N)6 (Arquès & Michel, 1990b). The problem investigated in this study is whether new properties can be identified in genes with other autocorrelation functions and also simulated with an oligonucleotide mixing model. The two autocorrelation functions analysing the occurrence probability of the i-motifs RRR(N)iRRR and YYY(N)iYYY simultaneously identify three new non-random genetic statistical properties: a short linear decrease, local maxima for i identical to 3[6] (i = 3, 9, etc) and a large exponential decrease. Furthermore, these properties are common to three different populations of eukaryotic non-coding genes: 5' regions, introns and 3' regions (see section 2). These three non-random properties can also be simulated by an independent mixing of the four oligonucleotides R8, Y8, RRRYRYRRR, YYYRYRYYY and large alternating R/Y series. The short linear decrease is a result of R8 and Y8, the local maxima for i identical to 3[6], of RRRYRYRRR and YYYRYRYYY, and the large exponential decrease, of large alternating R/Y series (section 3). The biological meaning of these results and their relation to the previous oligonucleotide mixing model are presented in the Discussion.
Animals↗
Analytical expression of the purine/pyrimidine codon probability after and before random mutations.
Recently, we proposed a new model of DNA sequence evolution (Arquès and Michel. 1990b. Bull. math. Biol. 52, 741-772) according to which actual genes on the purine/pyrimidine (R/Y) alphabet (R = purine = adenine or guanine, Y = pyrimidine = cytosine or thymine) are the result of two successive evolutionary genetic processes: (i) a mixing (independent) process of non-random oligonucleotides (words of base length less than 10: YRY(N)6, YRYRYR and YRYYRY are so far identified; N = R or Y) leading to primitive genes (words of several hundreds of base length) and followed by (ii) a random mutation process, i.e., transformations of a base R (respectively Y) into the base Y (respectively R) at random sites in these primitive genes. Following this model the problem investigated here is the study of the variation of the 8 R/Y codon probabilities RRR, ..., YYY under random mutations. Two analytical expressions solved here allow analysis of this variation in the classical evolutionary sense (from the past to the present, i.e., after random mutations), but also in the inverted evolutionary sense (from the present to the past, i.e., before random mutations). Different properties are also derived from these formulae. Finally, a few applications of these formulae are presented. They prove the proposition in Arquès and Michel (1990b. Bull. math. Biol. 52, 741-772), Section 3.3.2, with the existence of a maximal mean number of random mutations per base of the order 0.3 in the protein coding genes. They also confirm the mixing process of oligonucleotides by excluding the purine/pyrimidine contiguous and alternating tracts from the formation process of primitive genes.
Base Sequence↗
Identification and simulation of new non-random statistical properties common to different eukaryotic gene subpopulations.
The nucleotide distribution in protein coding genes, introns and transfer RNA genes of eukaryotic subpopulations (primates, rodent and mammals) is studied by autocorrelation functions. The autocorrelation function analysing the occurrence probability of the i-motif YRY(N)iYRY (YRY-function) in protein coding genes and transfer RNA genes of these three eukaryotic subpopulations retrieves the preferential occurrence of YRY(N)6YRY (R = purine = adenine or guanine, Y = pyrimidine = cytosine or thymine, N = R or Y). The autocorrelation functions analysing the occurrence probability of the i-motifs RRR(N)iRRR (RRR-function) and YYY(N)iYYY (YYY-function) identify new non-random genetic statistical properties in these three eukaryotic subpopulations, mainly: i) in their protein coding genes: local maxima for i identical to 6 [12] (peaks for i = 6, 18, 30, 42) with the RRR-function and local maxima for i identical to 8 [10] (peaks for i = 8, 18, 28) with the YYY-function; and ii) in their introns: local maxima for i identical to 3 [6] (peaks for i = 3, 9, 15) and a short linear decrease followed by a large exponential decrease both with the RRR- and YYY-functions. The non-random properties identified in eukaryotic intron subpopulations are modelised with a process of random insertions and deletions of nucleotides simulating the RNA editing.
Animals↗
A simulation of the genetic periodicities modulo 2 and 3 with processes of nucleotide insertions and deletions.
Recently, a new genetic process termed RNA editing has been identified showing insertions and deletions of nucleotides in particular RNA molecules. On the other hand, there are a few non-random statistical properties in genes: in particular, the periodicity modulo 3 (P3) associated with an open reading frame, the periodicity modulo 2 (P2) associated with alternating purine/pyrimidine stretches, the YRY(N)6YRY preferential occurrence (R = purine = adenine or guanine, Y = pyrimidine = cytosine or thymine, N = R or Y) representing a "code" of the DNA helix pitch, etc. The problem investigated here is whether a process of the type RNA editing can lead to the non-random statistical properties commonly observed in genes. This paper will show in particular that: The process of insertions and deletions of mononucleotides in the initial sequence [YRY(N)3]* [series of YRY(N)3] can lead to the periodicity modulo 2 (P2). The process of insertions and deletions of trinucleotides in the initial sequence [YRY(N)6]* [series of YRY(N)6] can lead to the periodicity modulo 3 (P3) and the YRY(N)6YRY preferential occurrence. Furthermore, these two processes lead to a strong correlation with the reality, namely the mononucleotide insertion/deletion process, with the 5' eukaryotic regions and the trinucleotide insertion/deletion process, with the eukaryotic protein coding genes.
Chromosome Deletion↗