RESUMO
We determine here the number and the list of maximal dinucleotide and trinucleotide circular codes. We prove that there is no maximal dinucleotide circular code having strictly less than 6 elements (maximum size of dinucleotide circular codes). On the other hand, a computer calculus shows that there are maximal trinucleotide circular codes with less than 20 elements (maximum size of trinucleotide circular codes). More precisely, there are maximal trinucleotide circular codes with 14, 15, 16, 17, 18 and 19 elements and no maximal trinucleotide circular code having less than 14 elements. We give the same information for the maximal self-complementary dinucleotide and trinucleotide circular codes. The amino acid distribution of maximal trinucleotide circular codes is also determined.
Assuntos
Aminoácidos/genética , Código Genético , Modelos Genéticos , Nucleotídeos/genética , Animais , Apicomplexa/genética , Bactérias/genética , Fungos/genética , Humanos , Modelos Teóricos , Nucleotídeos/química , Software , Vírus/genéticaRESUMO
We identify here a combinatorial property between circular code and genetic code. A circular code of 20 trinucleotides which allows to retrieve the reading frame has a permuted set of 20 trinucleotides which is a code, but not circular, coding the 20 amino acids in variant nuclear codes. This result is a contribution to the research field analysing the mathematical properties of genetic codes.
Assuntos
Aminoácidos , Código Genético/fisiologia , Modelos GenéticosRESUMO
INTRODUCTION: Exposure to environmental contaminants during pregnancy is one of the determinants of child's future health outcomes. The effect of environmental pollution on pregnant women living in heavily polluted areas is of special interest and, in this context, the Neonatal Environment and Health Outcomes (NEHO) cohort will focus on the investigation of (1) toxicants transferred from the environment to the mother and from the mother to the developing fetus and (2) the influence of toxicants on pregnancy outcomes, fetal development and health status during infancy. Because the human placenta is positioned at the interface between the maternal/external environment and the embryo, it can be considered a highly informative matrix regarding many key pregnancy events that can shape infant's future health. METHODS AND ANALYSIS: The NEHO cohort will enrol an estimated total of 800 pregnant women in three selected National Priority Contaminated Sites in southern Italy. Epidemiological data, concerning maternal health status, lifestyle and pregnancy, are obtained through questionnaires provided to the mother starting from the last 2 months of pregnancy. At delivery, maternal blood, umbilical cord blood and placenta tissue are collected to assess contaminant levels and to clarify how toxicants interact with the placental domain. Furthermore, placental transcriptome is studied in order to explore the interferences of toxicants on the role of the placenta in maternal/fetal interplay. Regular follow-up is planned at 6, 12 and 24 months. ETHICS AND DISSEMINATION: The study has been approved by all the Ethics Committees of the three National Priority Contaminated Sites involved: the Ethics Committee of the University Hospitals of Messina (18 September 2017, n. 9/2017); the Ethics Committee 'Catania 2' (11 July 2017, n. 38/2017/CECT2); the Ethics Committee of the Region of Calabria (20 July 2017, n. 173). Findings will be disseminated in the scientific community and on a regional basis for appropriate policy actions.
Assuntos
Exposição Ambiental/efeitos adversos , Desenvolvimento Fetal/efeitos dos fármacos , Locais de Resíduos Perigosos , Saúde do Lactente , Resultado da Gravidez/epidemiologia , Adolescente , Adulto , Exposição Ambiental/estatística & dados numéricos , Feminino , Sangue Fetal/química , Humanos , Lactente , Saúde do Lactente/estatística & dados numéricos , Recém-Nascido , Itália/epidemiologia , Estudos Longitudinais , Placenta/química , Placenta/metabolismo , Gravidez , Transcriptoma/efeitos dos fármacos , Adulto JovemRESUMO
In several papers Arquès and Michel studied the maximal circular codes consisting of words of length 3 (or trinucleotides) on the genetic alphabet {A, C, G, T}. We present here some additional information on these codes. In particular, we study the growth function of the self-complementary circular codes and we prove that among them exactly 528 are maximal.
Assuntos
Código Genético , Nucleotídeos/genética , Repetições de Trinucleotídeos , Algoritmos , Evolução Molecular , Crescimento , Repetições de Trinucleotídeos/genéticaRESUMO
In a recent paper, Michel and Pirillo prove that there are 24 dinucleotide circular codes of maximum cardinality over an alphabet of cardinality 4. In this paper we find the exact number of dinucleotide circular codes of maximum cardinality for any given (finite) cardinality of the alphabet. Moreover, we describe the structure of these codes.
Assuntos
Aminoácidos/genética , Código Genético , Modelos Genéticos , Nucleotídeos/análise , Animais , Biologia Computacional , Humanos , Reconhecimento Automatizado de PadrãoRESUMO
A new trinucleotide proposition is proved here and allows all the trinucleotide circular codes on the genetic alphabet to be identified (their numbers and their sets of words). This new class of genetic motifs, i.e. circular codes (or synchronizing genetic motifs), may be involved in the structure and the origin of the genetic code, and in reading frames of genes.