When the combined effects of alleles at different loci are equal
to the sum of their individual effects. (ORNL)
Adenine (A)
A nitrogenous base, one member of the base pair AT (adenine-thymine).
See also: base pair (ORNL)
Algorithm
A fixed procedure embodied in a computer program. (NCBI)
Alignment
The process of lining up two or more sequences to achieve
maximal levels of identity (and conservation, in the case
of amino acid sequences) for the purpose of assessing the
degree of similarity and the possibility of homology. (NCBI)
Alignment
Representation of a prediction of the amino acids in tertiary
structures of homologues that overlay in three dimensions.
Alignments held by SMART are mostly based on published observations
(see domain annotations for details), but are updated and
edited manually. (SMART)
All-alpha
A class that has the number of secondary structures in the
domain or common core described as 3-, 4-, 5-, 6- or multi-
helical. (SCOP)
All-beta
A class that includes two major fold groups: sandwiches and
barrels. The sandwich folds are made of two beta-sheets which
are usually twisted and pack so their strands are aligned.
The barrel fold are made of single beta-sheet that twists
and coils upon itself so, in most cases, the first strand
in the beta sheet hydrogen bond to the last strand. The strand
directions in the two opposite sides of a barrel fold are
roughly orthogonal. Orthogonal packing of sheets is also seen
in a few special cases of sandwich folds (SCOP)
Alternative form of a genetic locus; a single allele for each
locus is inherited from each parent (e.g., at a locus for
eye color the allele might result in blue or brown eyes).
(ORNL)
Allele
One of the variant forms of a gene at a particular locus,
or location, on a chromosome. Different alleles produce variation
in inherited characteristics such as hair color or blood type.
In an individual, one form of the allele (the dominant one)
may be expressed more than another form (the recessive one).
(NHGRI)
Allogeneic
Variation in alleles among members of the same species. (ORNL)
Alternative splicing
Different ways of combining a gene's exons to make variants
of the complete protein (ORNL)
Amino acid
Any of a class of 20 molecules that are combined to form proteins
in living things. The sequence of amino acids in a protein
and hence protein function are determined by the genetic code.
(ORNL)
Amplification
An increase in the number of copies of a specific DNA fragment;
can be in vivo or in vitro.
See also: cloning (ORNL)
Adding pertinent information such as gene coded for, amino
acid sequence, or other commentary to the database entry of
raw sequence of DNA bases.
See also: bioinformatics
(ORNL)
Anticipation
Each generation of offspring has increased severity of a genetic
disorder; e.g., a grandchild may have earlier onset and more
severe symptoms than the parent, who had earlier onset than
the grandparent.
See also: additive
genetic effects, complex trait
(ORNL)
Antisense
Nucleic acid that has a sequence exactly opposite to an mRNA
molecule made by the body; binds to the mRNA molecule to prevent
a protein from being made.
See also: transcription (ORNL)
Apoptosis
Programmed cell death, the body's normal method of disposing
of damaged, unwanted, or unneeded cells.
See also: cell (ORNL)
Array (of hairpins)
An assemble of alpha-helices that can not be described as
a bundle or a folded leaf. (SCOP)
Individual primary recombinant clones (hosted in phage, cosmid,
YAC, or other vector) that are placed in two-dimensional arrays
in microtiter dishes. Each primary clone can be identified
by the identity of the plate and the clone location (row and
column) on that plate. Arrayed libraries of clones can be
used for many applications, including screening for a specific
gene or genomic region of interest.
See also: library, genomic
library, gene chip
technology (ORNL)
Assembly
Putting sequenced fragments of DNA into their correct chromosomal
positions. (ORNL)
Autoradiography
A technique that uses X-ray film to visualize radioactively
labeled molecules or fragments of molecules; used in analyzing
length and number of DNA fragments after they are separated
by gel electrophoresis. (ORNL)
A gene on one of the non-sex chromosomes that is always expressed,
even if only one copy is present. The chance of passing the
gene to offspring is 50% for each pregnancy.
See also: autosome, dominant,
gene (ORNL)
A chromosome not involved in sex determination. The diploid
human genome consists of a total of 46 chromosomes: 22 pairs
of autosomes, and 1 pair of sex chromosomes (the X and Y chromosomes).
See also: sex chromosome
(ORNL)
