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.
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.
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 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.
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.
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.
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.
a gene carried on a sex chromosome (X or Y); only X linkage has clinical significance. See X-linked gene
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 (jen) [Ger. Gen, ult. fr Gr. genos, kind, race, descent]
AUTOSOMAL DOMINANT INHERITANCE
AUTOSOMAL DOMINANT INHERITANCE
The 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
autosomal dominant gene
A dominant gene that is found on any chromosome other than the X or Y chromosome.
autosomal recessive gene
A recessive gene that is found on any chromosome other than the X or Y chromosome.
A 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.
BRCA1 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.
A 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.
Nonallelic, independently located genes, neither of which will be expressed in the absence of the other.
cystic fibrosis transmembrane conductance regulator gene
The gene that codes for a protein that regulates the movement of ions, esp. chloride, across cell membranes.
dominant gene See: dominant
One 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 antigen
A gene located in the nonhomologous portion of the Y chromosome of males.
Any 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.
A 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 gene
One of the many genes that control the ability of leukocytes to respond to specific antigens. See: antigen; B cell; HLA complex; T cell
A gene that prevents the expression of another gene.
A 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).
A gene that creates a condition incompatible with life and usually results in the death of the fetus.
A gene that influences or alters the expression of other genes.
An altered gene that permanently functions differently than it did before its alteration.
A gene that controls the expression of other genes. See: operon
A 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.
A gene that has multiple effects.
posttranscriptional gene silencingRNA interference.
Rare traits responsible for early-onset Alzheimer's disease.
Tumor 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; retinoblastoma
A 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 characteristic
A gene that can control some specific activity of another gene.
sex-linked geneSex-linked characteristic.
A gene that determines the structure of polypeptide chains by controlling the sequence of amino acids.
A gene that increases a person's likelihood of contracting a heritable illness.
tumor suppressor gene
A gene that suppresses the growth of malignant cells. See: cancer
A 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.
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. How can genes cause breast cancer? We say genetics play a role in breast cancer but how is that possible …………I mean how can genes cause breast cancer?
A. Genes are the chemical entities and they can be changed of their set of structure inside a cell, when is exposed to radiation or any chemical through toxic food. Some genes like BRCA1 & 2 expanded as Breast Cancer 1 & 2 are helpful to prevent any cancer development of a single cell. These genes act as guards who prevent a cell to become cancerous. When anyone inherits this gene from parents and if they are defected they are also prone to breast cancer.
Q. can diet control breast cancer if the gene is supposed to be the cause of breast cancer?
A. No…I am sorry, it can`t. If it is radiation then diet cannot control. When we have exposure to toxic food and non toxic food where the free radical production is high, the free radical production can be controlled with the consumption of antioxidant rich food. Well it’s only a preventive step for the free radical rich food and not for the radiation induced cancer. Breast cancer is only treated with surgery and therapies. Diet plays a good role when your treatment is on, as it gives strength and overall wellbeing. More discussions about Gene