genetic penetrance

ge·net·ic pen·e·trance

the extent to which a genetically determined condition is expressed in an individual.

genetic

1. pertaining to reproduction or to birth or origin.

2. inherited.

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genetic abnormality

inherited defect, which may or may not be congenital.

genetic analysis

analysis of breeding and pedigree records to establish degrees of relationship between single animals and groups of animals. Segregation analysis with full-sibling families is an obvious technique.

genetic code

the manner in which the arrangement of nucleotides in the polynucleotide chain of a chromosome governs the transmission of genetic information to proteins, i.e. determines the sequence of amino acids in the polypeptide chain making up each protein synthesized by the cell. Genetic information is coded in DNA by means of four bases (two purines: adenine and guanine; and two pyrimidines: thymine and cystosine). Each adjacent sequence of three bases (a codon) determines which of the 20 amino acids will be inserted into the nascent polypeptide.

genetic complementation

see complementation.

genetic control of inherited disease

consists of preventing carrier animals from contributing their genes to succeeding generations of the population of which they are members.

genetic correlation

a change in an unselected character resulting from selection of another character during a breeding program.

genetic defects

defects of function or structure passed on from parents to offspring. Inherited defects.

genetic determination

see broad-sense heritability.

genetic disease resistance

inherited resistance to diseases caused by non-hereditary risk factors.

genetic dominance

see dominance (2).

genetic drift

see antigenic drift.

genetic engineering

the manipulation of genes by recombinant DNA technologies to produce chromosomal combinations that are unlikely to occur by natural means, for example the introduction of genes for insulin into a yeast cell which then produces insulin which can be purified and used as a therapeutic substance. See also recombinant DNA technology.

genetic etiology

disease caused by inheritance of specific disease without the intervention of other risk factors; established by strongly positive relationship in terms of genes held in common between the affected patient and other affected individuals.

genetic evaluation

assessment, for predictive purposes, of productive improvement or conformational characteristics, of the gain to be derived by the use of the animal in question in a breeding program.

genetic expressivity

see expressivity.

genetic heterogeneity

demonstrated by the way in which more than one disease with identical clinical signs can be inherited.

genetic immunization

use of a cloned genetically engineered gene with an encoded antigen to immunize the host against that antigen. See also DNA vaccine.

genetic map

the linear arrangement of genes along a chromosome. Called also linkage map.

genetic merit

inherited productivity or performance qualities.

mobile genetic elements

see transposable genetic elements (below).

genetic penetrance

see penetrance.

genetic production potential

inherited productivity but still influenced by environmental risk factors.

genetic resistance

genetically determined resistance to specified infectious agents.

genetic selection

selection of animals as breeding stock on the basis of known inherited characteristics.

transposable genetic elements

pieces of DNA varying in length from a few hundred to tens of thousands of base pairs found in both prokaryotic and eukaryotic cells that move from place to place in the chromosomes of a single cell; some are viruses. Called also mobile genetic elements or transposons.

genetic variance

that portion of the phenotypic variance of a trait in a population which can be attributed to genetic difference amongst individuals.