base composition


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base com·po·si·tion

the proportions of the four bases (adenine, cytosine, guanine, and thymine or uracil) present in DNA or RNA; usually expressed as the percentage (mol %) of G plus C.

base composition

The ratio of guanine + cytosine (GC) to adenine + thymine (AT) nucleotides in a nucleic acid; BC is usually expressed as a guanine + cytosine (G+C) value—e.g., 60% G+C. The GC content is of interest given that guanine and cytosine share three hydrogen bonds in double-stranded nucleic acids, compared to the two shared by adenine and thymine; the higher the GC content, the more stable the nucleic acid.
References in periodicals archive ?
8 which was selected from table 2 as a base composition for third stage melting.
The frequency of occurrence of each base composition was defined as the frequency that each expected base composition occurred over the set of 968 sequences in the database.
The codon usage of the 13 protein-coding genes and the base composition of 37 genes for three species were analyzed using the program MEGA 4.0.
Because size and base composition influence the retention of single-stranded DNA in DHPLC (4), multiplexing of two or more minisequencing reactions requires empirical determination of the retention times for the primers and extension products in DHPLC.
If codon usage is selected, then mutation pressure will not be the sole determinate of base composition in third positions, and the story told by Osawa becomes more complicated.
Alloying elements such as Cu, Ni and Mo are added to the base composition individually or in combination.
Base composition and codon usage were calculated with DNAStar software.
Phylogenetic trees were produced with a maximum likelihood method incorporating the GTR+ [GAMMA]+I model of nucleotide substitution, with the general time-reversible (GTR) substitution matrix, the base composition, the gamma ([GAMMA]) distribution of among-site rate variation, and the proportion of invariant sites (I) all estimated from the data.
Because of the length and base composition of the probe, the melting points were higher compared with the apoE probes.

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