25
Dec
2009
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Glossary

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D

D
Aspartic acid.
Darwinian fitness
(see fitness)
DDBJ
DNA Databank of Japan.
degenerate site
A nucleotide site in a codon that can be occupied by more than one nucleotide and still code for the same amino acid.
degree of divergence
The extent to which two homologous sequences differ from each other.
deleterious mutation
A mutation that lowers the fitness of its carriers.
deletion
The removal of one or more bases from a DNA sequence.
deltran
Delayed transformation in parsimony reconstruction.
denaturation
The loss of a protein's tertiary structure. Sometimes used as a synonym of DNA melting.
deterministic process
A process, the outcome of which can be predicted exactly from knowledge of initial conditions.
diagnostic position
(see informative site)
diploid
A chromosomal complement that contains two copies of each chromosome.
directional selection
A selective regime that changes the frequency of an allele in a specific direction, either toward fixation or toward elimination.
disjunction
The separation of homologous chromosomes during meiosis or the separation of complementary chromatids during mitosis.
distance
(see genetic distance)
divergence
The splitting of a taxonomic unit into two. (See also sequence divergence.)
domain
(see functional domain)
donor site
The 5' end of an intron.
dot matrix
A method of sequence alignment in which two sequences are written as column and row headings of a matrix and dots are put in those matrix elements that have identical column and row headings.
downstream
In the direction 3' of a reference point on a nucleic acid. In the direction of transcription.
drift
(see random genetic drift)
duplication
The presence or the creation of two copies of a DNA segment in the genome.
duplicative transposition
(see replicative transposition)