G gain of function mutation A mutation that results in an organism acquiring a new
function gamete A reproducitve cell with a haploid number of
chromosomes gap An insertion or a deletion. In sequece alignment, a pair
containing a null base. gap genes Developmental genes that play a rold in establishing
positional information with the Drosophila
embryo. gap penalty The assessment of how frequent a gap event occurs in
evolution in comparison with the frequency of occrrrence of
point substitutions. In alignment algorithms, either a
factor multiplied by the total length of gaps, or a function
multiplied by the number of gaps of a given length, which is
used to compare the likelihood of gaps and
substitutions. gapped alignment An alignment in which gaps are permitted gap extension penalty The length dependent term, l, of a gap penalty of the
form w=g+lx. Where w
is the gap penalty, g the
llenght-independent term, l
the length-dependent term, and
x the lenght of the gap. The
cost of extending a gap another character. gap opening penalty Also known as teh gap creation pentlty. The
length-independent term, g, of
a gap penalty of the form w=g+lx gap period One of two intermediate periods within the cell cycle GAPs GTPase activating proteins. A set of proteins that are
intermediates in the Ras signal transduction pathway. gap score The score assigned to a gap gcc A C compiler produced by the GNU Free Software
Foundation. GC Content The percentage of nucleotides in a genome that are G or
C gel retardation analysis A technique that identifies protein-binding sites on DNA
molecules by virtue of the effect that a bound protein has
on the mobility of the DNA fragments during gel
electrophoresis. gene A DNA segment containing biological information and hence
coding for an RNA and/or polypeptide molecule gene cloning insertion of a fragment of DNA, containing a gene, into a
cloning vector, and subsequent propagation of the
recombinant DNA molecule in a host organism. gene conversion A nonreciprocal recombination process resulting in a
sequece becoming identical with another. gene diversity A measure of genetic variability in a population. The
mean expected heterozygosity per locus in a population. gene duplication The production of two copies of a DNA sequence.
Specifically, the duplication of an entire gene sequence.
One method of evolution is by gene duplication followed by
mutation. gene expression The series of events by which the biological information
carried by a gene is released and made available to the
cell. Expressed genes include those that are transcribed
into mRNA and then translated into protein, and thost that
are transcribed into RNA, but not translated into protein
(e.g., transfer and ribosoman RNAs). gene family Two or more genes that are related by divergent evolution
from a common ancestor either by speciation or gene
duplication. Groups of closely related genes that make
similar products. gene fragment A gene relic consisting of short isolated regions from
within a gene gene mapping Determination of the relative positions of genes on a DNA
molecule and of the distance, in linkage units or physical
units, between them. gene pool All the genes in a sexually reproducing population. 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. general recombination Recombination between two homologous double-stranded DNA
molecules gene substitution The replacement of an allele that at one time was fixed
in the population by a second allele, this second allele
arising by mutation and increasing in frequency until itself
reaching fixation. The proces swherby a new mutant allele
reaches fixation (100%) in a population. gene superfamily A group of two or more evolutionary related multigene
families generation time The average time span between two successive generations.
Sometimes defined as the mean age of the parents at which
they give birth to their middle child. genes-within-genes Refers to a gene whose intron contains a second gene genetic code the rules that determine which triplet of nucleotides
codes for which amino acid during protein synthesis. genetic code matrix Also known as minimum base change scoring. A scroing
system for protein sequences where the distance between any
pair of residues is the minimum number of genetic footprinting A technique for the rapid functional analysis fo many
genes at once. genetic drift The fluctuation of allele frequnecies from generation to
generation caused by chance events, such as gamete
sampling. genetic marker A gene that exists as two or more readily distinguished
alleles and whose inheritance can therefore be followed
during a genetic cross, enabling the map position of the
gene to be determined. genetic profile the banding pattern revealed after electrophoresis of the
products of PCRs directed at a range of microsattelite
loci genetic redundancy The situation that occurs when two genes in the same
genome perform the same function. genetics The brach of biology devoted to the study of genes. gene tree A phylogenetic tree that has been constructied from one
or a few genes from each species. genome All the genetic material in the chromosomes of a
particular organism. Its size is generally given as its
total number of base pairs. genome projects research and technooogy development efforts aimed at
mapping and sequencing some or all of the genome of human
beings and other organisms. genome wide repeat Sequences that recur at many dispersed positions within a
genome. genomic imprinting Inactivation by methylation of a gene on one pair of
homologous chromosomes. genomic compartmentalization The existence of independently replicated genomes with a
cell. Usually, in reference to the genomes of
organelles. genomic library A colleciton of clones made from a set of randomly
generated overlapping DNA fragments representing the entire
genome of an organism. genotype The description of a specific organism interms of its
genome. This is opposed to phenotype which is a description
of an organism in terms of its expressed features geometric mean The nth root of the product of n terms. global alignment An optimal alignment that includes all characters from
each sequence. Global alignments may miss short regions of
high local similarity. Global alignments are most useful for
closely related sequeces of known homology. glycosylase An enzyme that cleaves the beta-N-glycosidic bond between
a base and the sugar component of a nucleotide, as part of
the base excision and mismatch repair process. glycosylation The attachment of sugar units to a polypeptide. G1 phase The first gap period of the cell cycle G2 phase The second gap period of the cell cycle Group I intron A type of intron found mainly in organelle genes Group II intron A type of intron found in organelle genes Group III intron A type of intron found in organelle genes groups A UNIX command that will show the groups that user
belongs to Grail A program for predicting coding regions, intron/exon
boundaries of genomic sequences. GRASP A molecular modeling program grep Global regular expression parser - A UNIX command that
lets you search for the presence of a string within a
file. Genome survey sequences - This GenBank division is
similar in nature to the EST division,except that its
sequences are genomic in origin, rather than cDNA (mRNA) the
GSS division contains (but i snot limited to ) the following
types of data: random "single-pass read" genomic sequences;
single-pass reads from cosmid/BAC/YAC ends; exon-trapped
genomic sequences; ALU PCR sequences. GU-AG intron the commonest type of intron in eukaryotic nuclear genes.
The first two nucleotides of the intron are 5'-GU-3' and the
last two are 5'-AG-3' GUI Graphical User Interface. Refers to software front ends
that rely on pictures and icons to direct the interaction of
users with the application. gyrase
