gene bank


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gene bank

  1. a collection of clones containing all the genes of a particular organism, such as E. coli. The bank can be prepared by isolating the DNA from an organism, digesting it with a RESTRICTION ENZYME and cloning the restriction fragments. It can be maintained for many years, to provide a repository of cloned genetic material.
  2. a collection of many lines of a particular crop plant, seeds or pollen used as a genetic resource by plant breeders; or of sperm, ova, embryos in the case of animals.
  3. a collection of DNA sequences (genetic database) stored at a specific Internet site, such as Genbank (http://www.ncbi.nlm.nih.gov). See also BIOINFORMATICS.

gene

the unit of heredity most simply defined as a specific segment of DNA, usually in the order of 1000 nucleotides, that specifies a single polypeptide. Many phenotypic characteristics are determined by a single gene, while others are multigenic. Genes are specifically located in linear order along the single DNA molecule that makes up each chromosome. All eukaryotic cells contain a diploid (2n) set of chromosomes so that two copies of each gene, one derived from each parent, are present in each cell; the two copies often specify a different phenotype, i.e. the polypeptide will have a somewhat different amino acid composition. These alternative forms of gene, both within and between individuals, are called alleles. Genes determine the physical (structural genes), the biochemical (enzymes), physiological and behavioral characteristics of an animal.
The formation of gametes (sperm, ova) involves a process of meiosis, which allows crossing over between four pairs of chromosomes, two derived from each parent, which means that new forms of a particular chromosome are created. Gamete formation also results in cells (gametes) with a haploid (n) set of chromosomes that in fertilization creates a new individual, which is a recombinant of 2n chromosomes, half derived by way of the ovum from the mother and half via the spermatozoa from the father.
Changes in the nucleotide sequence of a gene, either by substitution of a different nucleotide or by deletion or insertion of other nucleotides, constitute mutations which add to the diversity of animal species by creating different alleles and can be used as a basis for genetic selection of different phenotypes. Some mutations, be they a single base change in a single gene or a major deletion, are lethal.

gene action
the way in which genes exert their effects on tissues or processes, e.g. by being dominant or recessive, or partially so, being absent, being sex-linked, being involved in chromosomal aberrations.
allelic g's
different forms of a particular gene usually situated at the same position (locus) in a pair of chromosomes.
gene amplification
see gene duplication (below).
gene bank
the collection of DNA sequences in a given genome. Called also gene library.
barring gene
responsible for the barred pattern on the feathers of Barred Plymouth Rock birds.
gene box
see box (4).
gene clone
see clone.
gene cluster
a group of related genes derived from a common ancestral gene, located closely together on the same chromosome. Called also multigene family.
complementary g's
two independent pairs of nonallelic genes, neither of which is functional without the other.
gene conversion
a non-reciprocal exchange of DNA elements during meiosis which results in a functional rearrangement of chromosomal DNA.
dhfr gene
dihydrofolate reductase gene; an enzyme required to maintain cellular concentrations of H2 folate for nucleotide biosynthesis, and which has been used as a 'selective marker'; cells lacking the enzyme only survive in media containing thymidine, glycine and purines; mutant cells (dhfr) transfected with DNA that is dhfr′ can be selectively grown in medium lacking these elements.
diversity (D) gene
genes located in diversity (D) segment; contribute to the hypervariable region of immunoglobulins.
dominant gene
one that produces an effect (the phenotype) in the organism regardless of the state of the corresponding allele. Examples of traits determined by dominant genes are short hair in cats and black coat color in dogs.
gene duplication
as a result of non-homologous recombination, a chromosome carries two or more copies of a gene.
gene expression
gene frequency
the proportion of the substances or animals in the group which carry a particular gene.
holandric g's
genes located on the Y chromosome and appearing only in male offspring.
immune response (Ir) g's
genes of the major histocompatibility complex (MHC) that govern the immune response to individual immunogens.
jumping gene
see mobile dna.
gene knockout
replacement of a normal gene with a mutant allele, as in gene knockout mice.
lethal gene
one whose presence brings about the death of the organism or permits survival only under certain conditions.
gene library
see gene bank (above).
gene locus
see locus.
mutant gene
one that has undergone a detectable mutation.
non-protein encoding gene
the final products of some genes are RNA molecules rather than proteins.
overlapping g's
when more than one mRNA is transcribed from the same DNA sequence; the mRNAs may be in the same reading frame but of different size or they may be in different reading frames.
gene pool
total of all genes possessed by all members of the population which are capable of reproducing during their lifetime.
gene probe
see probe (2).
recessive gene
one that produces an effect in the organism only when it is transmitted by both parents, i.e. only when the individual is homozygous.
regulator gene, repressor gene
one that synthesizes repressor, a substance which, through interaction with the operator gene, switches off the activity of the structural genes associated with it in the operon.
reporter gene
one that produces products which can be measured and therefore used as an indicator of whether a DNA construct has successfully been transferred.
sex-linked gene
one that is carried on a sex chromosome, especially an X chromosome.
gene splicing
structural gene
nucleotide sequences coding for proteins.
gene therapy
the insertion of functional genes into cells of the host in order to alter its phenotype, usually used to treat an inherited defect.
gene transcription
gene transfer
tumor suppressor g's
a class of genes that encode proteins that normally suppress cell division that when mutated allow cells to continue unrestricted cell division and may result in a tumor.
References in periodicals archive ?
In terms of structure, we have an international advisory council, which I chair, and it consists of individuals from different disciplines: scientists, gene bank specialists, and members of civil society organizations, who advise on policy issues.
The Trust will establish an endowment that will provide support for gene bank conservation and capacity-building for developing countries.
Besides the patent issue, the panel is also looking into allegations that he had not handed over GM seeds supposed to have been developed by him when he left the NRCPB to join the gene bank two years back.
TUNIS, April 14, 2011 (TAP) - A training session in management of gene banks started on April 12, 2011.
There are 10,000 plant resources in the gene bank which was previously established in Ankara and 50,000 plant resources in the gene bank in the western province of Izmir.
First the Svalgaard Seedbank, then the Nordic Gene Bank for Farm Animals.
With all the selective breeding and all sorts of human interference, this is a useful gene bank.
The volume includes highlighted case studies, and color plates of plants, interaction with local peoples for successful wild relative crop conservation, monitoring activities, a gene bank, and native plant nursery.
Apparently the gene bank was exhausted and it was no more.
However, the gene has been included at the National Centre of Biotechnology Information's gene bank in Maryland, US, for researchers around the world to study.
Some are sent free to members, plus we also keep some back in our cold store gene bank at Wellesborough where they are kept at a temperature of minus 20 degrees.
To date, the IMF has conducted more than 100 educational seminars worldwide, maintains a world-renowned hotline, and operates Bank on a Cure[R], a unique gene bank to advance myeloma research.