A space introduced into an alignment to compensate for insertions
and deletions in one sequence relative to another. To prevent
the accumulation of too many gaps in an alignment, introduction
of a gap causes the deduction of a fixed amount (the gap score)
from the alignment score. Extension of the gap to encompass
additional nucleotides or amino acid is also penalized in the
scoring of an alignment. (NCBI)
Gap
A position in an alignment that represents a deletion within
one sequence relative to another. Gap penalties are requirements
for alignment algorithms in order to reduce excessively-gapped
regions. Gaps in alignments represent insertions that usually
occur in protruding loops or beta-bulges within protein structures.
(SMART)
GC-rich area
Many DNA sequences carry long stretches of repeated G and
C which often indicate a gene-rich region. (ORNL)
The fundamental physical and functional unit of heredity.
A gene is an ordered sequence of nucleotides located in a
particular position on a particular chromosome that encodes
a specific functional product (i.e., a protein or RNA molecule).
See also: gene expression
(ORNL)
Gene amplification
Repeated copying of a piece of DNA; a characteristic of tumor
cells.
See also: gene, oncogene
(ORNL)
Development of cDNA microarrays from a large number of genes.
Used to monitor and measure changes in gene expression for each
gene represented on the chip. (ORNL)
The process by which a gene's coded information is converted
into the structures present and operating in the cell. Expressed
genes include those that are transcribed into mRNA and then
translated into protein and those that are transcribed into
RNA but not translated into protein (e.g., transfer and ribosomal
RNAs). (ORNL)
Gene family
Group of closely related genes that make similar products.
(ORNL)
Determination of the relative positions of genes on a DNA
molecule (chromosome or plasmid) and of the distance, in linkage
units or physical units, between them. (ORNL)
Predictions of possible genes made by a computer program based
on how well a stretch of DNA sequence matches known gene sequences
(ORNL)
Gene product
The biochemical material, either RNA or protein, resulting
from expression of a gene. The amount of gene product is used
to measure how active a gene is; abnormal amounts can be correlated
with disease-causing alleles. (ORNL)
Incorporation of new DNA into and organism's cells, usually
by a vector such as a modified virus. Used in gene therapy.
See also: mutation, gene
therapy, vector (ORNL)
The sequence of nucleotides, coded in triplets (codons) along
the mRNA, that determines the sequence of amino acids in protein
synthesis. A gene's DNA sequence can be used to predict the
mRNA sequence, and the genetic code can in turn be used to predict
the amino acid sequence. (ORNL)
Genetic counseling
Provides patients and their families with education and information
about genetic-related conditions and helps them make informed
decisions. (ORNL)
Genetic discrimination
Prejudice against those who have or are likely to develop
an inherited disorder. (ORNL)
An organism in which different cells contain different genetic
sequence. This can be the result of a mutation during development
or fusion of embryos at an early developmental stage. (ORNL)
Genetic polymorphism
Difference in DNA sequence among individuals, groups, or populations
(e.g., genes for blue eyes versus brown eyes). (ORNL)
Genetic predisposition
Susceptibility to a genetic disease. May or may not result
in actual development of the disease. (ORNL)
Analyzing an individual's genetic material to determine predisposition
to a particular health condition or to confirm a diagnosis of
genetic disease. (ORNL)
All the genetic material in the chromosomes of a particular
organism; its size is generally given as its total number of
base pairs. (ORNL)
Genome project
Research and technology-development effort aimed at mapping
and sequencing the genome of human beings and certain model
organisms.
See also: Human Genome
Initiative (ORNL)
A collection of clones made from a set of randomly generated
overlapping DNA fragments that represent the entire genome
of an organism.
See also: library, arrayed
library (ORNL)
Sperm and egg cells and their precursors. Germ cells are haploid
and have only one set of chromosomes (23 in all), while all
other cells have two copies (46 in all). (ORNL)
Germ line
The continuation of a set of genetic information from one
generation to the next.
See also: inherit (ORNL)
An experimental process of inserting genes into germ cells
or fertilized eggs to cause a genetic change that can be passed
on to offspring. May be used to alleviate effects associated
with a genetic disease.
See also: genomics, somatic
cell gene therapy. (ORNL)
The alignment of two nucleic acid or protein sequences over
their entire length. (NCBI)
Greek-key
a topology for a small number of beta sheet strands in which
some interstrand connections going across the end of barrel
or, in a sandwich fold, between beta sheets. (SCOP)
Guanine (G)
A nitrogenous base, one member of the base pair GC (guanine
and cytosine) in DNA.
See also: base pair, nucleotide
(ORNL)
