gene (jēn) the biologic unit of heredity, self-reproducing and located at a definite position (locus) on a particular chromosome.
Gene
gene
gene [jēn]
gene,
gene,
gene
Patient discussion about gene.
allelic gene allele.
chimeric gene an artificial gene constructed by juxtaposition of fragments of unrelated genes or other DNA segments, which may themselves have been altered.
complementary genes two independent pairs of nonallelic genes, neither of which will produce its effect in the absence of the other.
dominant gene one that is phenotypically expressed when present in homozygotes or heterozygotes.
H gene , histocompatibility gene one that determines the specificity of tissue antigenicity (HLA antigens), and thus the compatibility of donor and recipient in tissue transplantation and blood transfusion.
holandric genes genes in the nonhomologous region of the Y chromosome.
immune response (Ir) genes genes of the major histocompatibility complex that govern the immune response to individual immunogens.
Is genes genes that govern the formation of suppressor T lymphocytes.
lethal gene one whose presence brings about the death of the organism or permits survival only under certain conditions.
mutant gene one that has undergone a detectable mutation.
operator gene one serving as a starting point for reading the genetic code, and which, through interaction with a repressor, controls the activity of structural genes associated with it in the operon.
recessive gene one that produces an effect in the organism only when it is homozygous.
regulator gene , regulatory gene
1. in genetic theory, one that synthesizes repressor, a substance that through interaction with the operator gene switches off the activity of the structural genes associated with it in the operon.
2. any gene whose product affects the activity of other genes.
repressor gene regulator g. (1).
sex-linked gene one carried on a sex chromosome, especially on an X chromosome.
split gene a gene containing multiple exons and at least one intron.
structural gene one that specifies the amino acid sequence of a polypeptide chain.
gene (j n)n. A hereditary unit that occupies a specific location on a chromosome, determines a particular characteristic in an organism by directing the formation of a specific protein, and is capable of replicating itself at each cell division. |
Gene
A building block of inheritance, which contains the instructions for the production of a particular protein, and is made up of a molecular sequence found on a section of DNA. Each gene is found on a precise location on a chromosome.
Mentioned in: Acoustic Neuroma, Albinism, Birth Defects, Blood Typing and Crossmatching, Cutis Laxa, Familial Polyposis, Gene Therapy, Genetic Testing, Periodic Paralysis, Phenylketonuria, Polydactyly and Syndactyly, Porphyrias, Prader-Willi Syndrome, Pseudoxanthoma Elasticum, Retinoblastoma, Situs Inversus, Von Willebrand Disease, Wilson Disease, Wiskott-Aldrich Syndrome
gene
[jēn]
Etymology: Gk, genein, to produce
the biologic unit of inheritance, consisting of a particular nucleotide sequence within a DNA molecule that occupies a precise locus on a chromosome and codes for a specific polypeptide chain. In diploid organisms, which include humans and other mammals, genes occur as paired alleles. Kinds of genes include complementary genes, mutant genes, operator genes, pleiotropic genes, regulator genes, structural genes, and supplementary genes. See also chromosome, cistron, deoxyribonucleic acid, operon.
gene [jēn]
one of the biologic units of heredity, self-reproducing, and located at a definite position (locus) on a particular chromosome. Genes make up segments of the complex deoxyribonucleic acid (DNA) molecule that controls cellular reproduction and function. There are thousands of genes in the chromosomes of each cell nucleus; they play an important role in heredity because they control the individual physical, biochemical, and physiologic traits inherited by offspring from their parents. Through the genetic code of DNA they also control the day-to-day functions and reproduction of all cells in the body. For example, the genes control the synthesis of structural proteins and also the enzymes that regulate various chemical reactions that take place in a cell.
The gene is capable of replication. When a cell multiplies by mitosis each daughter cell carries a set of genes that is an exact replica of that of the parent cell. This characteristic of replication explains how genes can carry hereditary traits through successive generations without change.
The gene is capable of replication. When a cell multiplies by mitosis each daughter cell carries a set of genes that is an exact replica of that of the parent cell. This characteristic of replication explains how genes can carry hereditary traits through successive generations without change.
allelic gene allele.
complementary g's two independent pairs of nonallelic genes, neither of which will produce its effect in the absence of the other.
DCC gene (deleted in colorectal carcinoma) a gene normally expressed in the mucosa of the colon but reduced or absent in a small proportion of patients with colorectal cancer.
dominant gene one that produces an effect (the phenotype) in the organism regardless of the state of the corresponding allele. An example of a trait determined by a dominant gene is brown eye color. See also heredity.
histocompatibility gene one that determines the specificity of tissue antigenicity (hla antigens) and thus the compatibility of donor and recipient in tissue transplantation and blood transfusion.
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 that govern the immune response to individual immunogens.
immune suppressor (Is) g's genes that govern the formation of suppressor T lymphocytes.
immunoglobulin g's the genes coding for immunoglobulin heavy and light chains, which are organized in three loci coding for κ light chains, λ light chains, and heavy chains.
K-ras gene a type of oncogene.
lethal gene one whose presence brings about the death of the organism or permits survival only under certain conditions.
major gene a gene whose effect on the phenotype is always evident, regardless of how this effect is modified by other genes.
mutant gene one that has undergone a detectable mutation.
operator gene one serving as a starting point for reading the genetic code, and which, through interaction with a repressor, controls the activity of structural genes associated with it in the operon.
gene pool all of the genes possessed by all of the members of a population that will reproduce.
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. See also heredity.
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.
sex-linked gene a gene carried on a sex chromosome (X or Y); only X linkage has clinical significance. See X-linked gene.
gene splicing recombinant dna technology.
structural gene one that forms templates for messenger RNA and is thereby responsible for the amino acid sequence of specific polypeptides.
tumor suppressor gene a gene whose function is to limit cell proliferation and loss of whose function leads to cell transformation and tumor growth; called also antioncogene.
X-linked gene a gene carried on the X chromosome; the corresponding trait, whether dominant or recessive, is always expressed in males, who have only one X chromosome. the term “X-linked” is sometimes used synonymously with “sex-linked,” since no genetic disorders have as yet been associated with genes on the Y chromosome.
gene,
n the unit of heredity that is made of a DNA sequence occupying a specific location on a chromosome and codes for a polypeptide chain.
gene pool,
n the sum of genes in a given population.
gene,
n See family practice.
(ho´meoboks”),
n a gene containing a DNA sequence called the homeobox, which is very similar between species and encodes a DNA-binding domain in the resulting protein molecule. Homeobox genes usually play a role in controlling development of the organism.
n a gene containing a DNA sequence called the homeobox, which is very similar between species and encodes a DNA-binding domain in the resulting protein molecule. Homeobox genes usually play a role in controlling development of the organism.
gene locus,
n See locus, gene.
gene, sex-linked,
n a gene located in a sex chromosome.
gene therapy,
n a procedure that involves injection of “health genes” into the bloodstream of a patient to cure or treat a hereditary disease or similar illness.
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
see expression (3).
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
see 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
see transcription.
gene transfer
see recombination.
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.
gene
The unit of heredity which determines, or contributes to, one inherited feature of an organism (e.g. eye colour). Physically, a gene is composed of a defined DNA sequence, located at a specific place (locus) along the length of a chromosome and transmitted by a parent to its offspring. The DNA sequence of nucleotide bases (adenine, cytosine, guanine and thymine) encodes a specific sequence of amino acids corresponding to a particular protein. If the DNA sequence at one locus is identical on a pair of homologous chromosomes the organism is referred to as homozygous (homozygote) and if the DNA sequence is not identical it is referred to as heterozygous (heterozygote). The total effect of all genes influences the development and functioning of all organs and systems in the body. See chromosome; genome; inheritance; mutation; pedigree.
gene
Genetics Classic mendelian definition A unit of inheritance carrying a single trait and recognized by its ability to mutate and undergo recombination–this definition is widely recognized as primitive Current definition A segment of
DNA nucleotides, comprised of 70 to 30,000 bp including introns, that encodes a sequence of mRNA, capable of giving rise to a functional producte–eg, enzyme, hormone, receptor–polypeptide; genes may be structural, and form cell
components, or functional, and have a regulatory role; a biological unit of heredity which is self-reproducing and located at a definite position on a particular chromosome; genes are working subunits of DNA; each of the body's 50,000 to 100,000
genes contains the code for a specific product, commonly for making a specific protein–eg an enzyme; the functional and physical unit of heredity passed from parent to offspring. See Cellular oncogene, Crime gene, Expressed gene, Functional
gene, Housekeeping gene, Lethal gene, Mutable gene, Mutator gene, Pseudogene, Reporter gene, Structural gene, Suppressor gene, Tumor suppressor. Cf Chromosome.
Patient discussion about gene.
Q. What Is the BRCA Gene? We have a history of breast cancer in our family and my doctor advised me to get genetic testing for the BRCA gene. How is this gene related to breast cancer?
A. BRCA1 (breast cancer 1, early onset) is a human gene that belongs to a class of genes known as tumor suppressors, which maintains gene integrity to prevent uncontrolled proliferation (what causes cancer cells to develop). Variations in the gene have been implicated in a number of hereditary cancers, mainly breast, ovarian and prostate. The BRCA family of genes are known today to give a significant increased risk for breast cancer in families. A women should be tested if a number of women in her family have had breast cancer throughout their life, especially at a young age.
Q. I was shocked to note that genes play a vital role in building muscles Is this possible? I am , 20 years old. I am always dreaming to build muscle like my favorite hero who maintains 8 abs. Anybody can dream but to live that dream is a difficult task. Out of curiosity, I had discussed my desire to build muscles with my friends. But I was shocked to note that genes play a vital role in building muscles. My family doesn’t have a history of muscles and this fact has put me in to a difficult situation. Is this possible…If so, how can I live my dream? If the family doesn’t have a history of muscle growth, then what happens to the generation which follows them? I need a positive feedback to my query……
A. there's a genetic potential for fitness, like there is a genetic connection and potential for inelegance. but no matter how smart are your parents- if you won't study you won't live that potential, and some one who doesn't have that genetic ability and will study- will be better. the same thing with physical fitness.
Q. Is celiac genetic? I have one son with celiac disease from my first marriage and me second wife is now pregnant,I was wondering what are the chances for this soon to be born daughter of mine to have celiac as well- if I maybe carry the genetic flaw and is there a way to find out?
A. Celiac disease is a very common illness (about 1 in a 100 people suffer from it in different levels), and it is known to have a strong genetic connection. However, there is not one specific mutation that you can get genetic testing to see if you are carrying it. Your soon to be born daughter will have a higher chance than the regular population to suffer from the disease, but it does not necessarily mean she will.
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