Biomaterial Database

Evolution of DNA structure: direction, mechanism, rate. 1976

A L Mazin

On the basis of the results of an analysis of frequencies of pyrimidine oligonucleotides, the degree of pyrimidine clustering of DNA in species from different taxa has been determined. A tendency for an increase in the index of clustering of DNA was revealed in the sequence: invertebrates, fishes, amphibians, reptiles, birds, mammals. A mechanism is postulated, according to which the increase in the degree of clustering of DNA d-ring the evolution may be associated with the accumulation of mutations, Purine equalibrium Pyrimidine transversions, resulting in a selective enrichment of one of the chains of DNA with pyrimidines and the other- with purines, i.e. in an increase in the degree of purine-pyrimidine imbalance (asymmetry) of DNA complementary chains. This mechanism of DNA evolution is supported by the presence of positive correlation between the degree of clustering and the degree of the chain asymmetry of natural DNAs, as well as the character of the amino acid substitutions in cytochromes c in different species. The progressive evolution of different groups of organisms on the whole may have been accompanied by an acceleration of the rates of evolution of the DNA structure. On the basis of the amino acid sequence of cytochromes c in different species the degree of clustering and the degree of the chain asymmetry of the corresponding structural genes of DNA was found to have a general tendency towards an increase in the following order: invertebrates, fishes, amphibians, reptiles, birds, mammals. Thus, evolution of cytochrome c cistron is a vector process based on a selection of mutations which, on the one hand, are neurtral to protein, and, on the other hand, result in the sense chain of DNA being enriched with pyrimidines and the nonsense one (and the corresponding mRNA)- with purines. Hence, it is the polynucleotide template rather than protein, that must have been the "object of selection". The frequency of substitutions in cytochromes c cistron for vertebrates is 1.56x13(-9) per nucleotide per year. It is believed that the evolutionary modification of the DNA structure may be associated with an increase in the interference resistance of the translation, i.e. with selection for codons of highest readout stability.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D003574	Cytochrome c Group	A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)	Cytochromes Type c,Group, Cytochrome c,Type c, Cytochromes
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular