Recessive gene

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Related to Recessive gene: Recessive allele


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.
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.
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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

recessive allele


recessive gene

an ALLELE that only shows its effect in the PHENOTYPE when present in a HOMOZYGOTE. When paired with a dominant allele the effect of the recessive allele is hidden. see RECESSIVE CHARACTER.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Recessive gene

A type of gene that is not expressed as a trait unless inherited by both parents.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The study called on marriage officials to make sure prospective couples abide by the law and are pre-screened for the presence of shared recessive genes, as well as HIV and hepatitis B and C.
Segregating lines in RIL populations were identified by the occurrence of various disease reactions and a 1 resistant: 3 susceptible ratio among the 20 individual plants rated (assuming single recessive gene control of resistance).
"These anecdotal observations strongly suggest the presence of a recessive gene or genes," said Wang.
It has a unique recessive gene which produces white hair instead of black.
Most frequently the pattern of inheritance indicates a recessive gene, but dominant and codominant mutations also appear.
Patients may also have a recessive gene, and may pass the disease to their children even if they do not exhibit its symptoms.
RECESSIVE GENE Recessive genes are "weak" and are always dominated by strong, dominant genes unless two for a particular trait get together because they're donated by each parent.
But, researchers also determined that he carried the recessive gene which blocks this ability.
Early flowering in this mutant is controlled by a single recessive gene. LGRU ef may be useful as a tropical japonica genetic stock or breeding source for early maturity.
White tigers are a colour morph of the tiger, caused by the recessive gene 'chinchilla albinistic'.
It can't just be that research for Newsnight has uncovered the frankly less-than-startling fact that children born to in-bred families are 13 times more likely to have recessive gene illnesses than the general population.
Based on these data, we conclude that a single recessive gene is responsible for the short-internode condition.