| 释义 |
dominant gene
Thesaurus| Noun | 1. |  dominant gene - gene that produces the same phenotype in the organism whether or not its allele identical; "the dominant gene for brown eyes"cistron, gene, factor - (genetics) a segment of DNA that is involved in producing a polypeptide chain; it can include regions preceding and following the coding DNA as well as introns between the exons; it is considered a unit of heredity; "genes were formerly called factors" |
EncyclopediaSeegeneDominant gene
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.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" >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 complex" >major histocompatibility complex that govern the immune response to individual immunogens.immune suppressor (Is) g's genes that govern the formation of suppressor lymphocytes" >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 gene" >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.dom·i·nance of traitsan expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). At a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant.dom·i·nance of traits (dom'i-năns trāts) An expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). At a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant. gene (jen) [Ger. Gen, ult. fr Gr. genos, kind, race, descent]  AUTOSOMAL DOMINANT INHERITANCE AUTOSOMAL DOMINANT INHERITANCEThe basic unit of heredity, made of DNA, the code for a specific protein. Each gene occupies a certain location on a chromosome. Genes are self-replicating sequences of DNA nucleotides, subject to random structural changes (mutations). Hereditary traits are controlled by pairs of genes in the same position on a pair of chromosomes. These alleles may be either dominant or recessive. When both pairs of an allele are either dominant or recessive, the individual is said to be homozygous for the traits coded by the gene. If the alleles differ (one dominant and one recessive), the individual is heterozygous. See: illustration; chromosome; DNA; RNAautosomal dominant geneA dominant gene that is found on any chromosome other than the X or Y chromosome.autosomal recessive geneA recessive gene that is found on any chromosome other than the X or Y chromosome.BRCA1 geneA breast cancer gene found in a small percentage of patients with this malignancy, and carried by some individuals who will develop breast cancer later in life. Patient careBRCA1 Gene Mutation: Patient care focuses on determining the family history of the patient and referral to a genetic counselor with expertise in this mutation when appropriate. BRCA2 geneA breast cancer gene found in a small number of patients with breast and ovarian cancers, and carried by some individuals who will develop breast cancer later in life.complementary genesNonallelic, independently located genes, neither of which will be expressed in the absence of the other. cystic fibrosis transmembrane conductance regulator geneThe gene that codes for a protein that regulates the movement of ions, esp. chloride, across cell membranes. dominant gene See: dominanthistocompatibility geneOne of the genes composing the HLA complex that determines the histocompatibility antigenic markers on all nucleated cells. These genes create the antigens by which the immune system recognizes “self” and determines the “nonself” nature of pathogens and other foreign antigens. These antigens are crucial determinants of the success or failure of organ transplantation. See: histocompatibility locus antigenholandric geneA gene located in the nonhomologous portion of the Y chromosome of males.homeobox geneAny transcription factor that regulates the growth, differentiation, replication, and movement of cells in the body. These genes influence both normal and abnormal embyological development and the development or suppression of malignant tumors. housekeeping geneA gene expressed in nearly every cell and every tissue of an organism, i.e., one that encodes a protein fundamental to cellular activity throughout the organism.immune response geneOne of the many genes that control the ability of leukocytes to respond to specific antigens. See: antigen; B cell; HLA complex; T cellinhibiting geneA gene that prevents the expression of another gene.interleukin-28B geneA genetic variant that increases the likelihood of having a favorable to response to antiviral treatment for chronic hepatitis C, genotype 1 infection (traditionally the most resistant hepatitis C genotype).lethal geneA gene that creates a condition incompatible with life and usually results in the death of the fetus. modifying geneA gene that influences or alters the expression of other genes.mutant geneAn altered gene that permanently functions differently than it did before its alteration.operator geneA gene that controls the expression of other genes. See: operongene p53A gene thought to be important in controlling the cell cycle, DNA repair and synthesis, and programmed cell death (apoptosis). Mutations of p53 have occurred in almost half of all types of cancer, arising from a variety of tissues. Mutant types may promote cancer. The normal, wild-type gene produces a protein important in tumor suppression. pleiotropic geneA gene that has multiple effects. posttranscriptional gene silencingRNA interference.presenilin geneRare traits responsible for early-onset Alzheimer's disease.RB geneTumor suppressor gene encoding for the retinoblastoma (RB) protein, mutations of which are associated with various human tumors, including retinoblastoma, osteosarcoma, some leukemias, and some adenocarcinomas. See: tumor suppressor gene; retinoblastomarecessive geneA trait that is not expressed unless it is present in the genes received from both parents. A recessive trait may be apparent in the phenotype only if both alleles are recessive. Synonym: recessive characteristicregulator geneA gene that can control some specific activity of another gene.sex-linked geneSex-linked characteristic.structural geneA gene that determines the structure of polypeptide chains by controlling the sequence of amino acids.susceptibility geneA gene that increases a person's likelihood of contracting a heritable illness.tumor suppressor geneA gene that suppresses the growth of malignant cells. See: cancerX-linked geneA gene on the X chromosome for which there is no corresponding gene on the Y chromosome. X-linked genes (e.g., the gene for red-green color blindness) are expressed but in males even these genes are recessive because there is no correponding gene to dominate them. Dominant geneA gene, whose presence as a single copy, controls the expression of a trait.Mentioned in: Genetic Testingdominant gene
Words related to dominant genenoun gene that produces the same phenotype in the organism whether or not its allele identicalRelated Words |