genetic drift(redirected from Gene drift)
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a change in the frequencies of genetic traits or allele frequencies over generations.
Variation in gene frequencies in a population due to chance rather than natural selection, mutation, or immigration.
a gradual change in the allelic frequencies within a population as a result of chance. The smaller a population is, the greater is the tendency for variation within each generation so that eventually small, isolated, inbreeding groups become genetically quite different from their ancestors. Also called random genetic drift.
genetic driftsee RANDOM GENETIC DRIFT.
1. pertaining to reproduction or to birth or origin.
inherited defect, which may or may not be congenital.
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.
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 control of inherited disease
consists of preventing carrier animals from contributing their genes to succeeding generations of the population of which they are members.
a change in an unselected character resulting from selection of another character during a breeding program.
defects of function or structure passed on from parents to offspring. Inherited defects.
see broad-sense heritability.
genetic disease resistance
inherited resistance to diseases caused by non-hereditary risk factors.
see dominance (2).
see antigenic drift.
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.
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.
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.
demonstrated by the way in which more than one disease with identical clinical signs can be inherited.
use of a cloned genetically engineered gene with an encoded antigen to immunize the host against that antigen. See also DNA vaccine.
the linear arrangement of genes along a chromosome. Called also linkage map.
inherited productivity or performance qualities.
mobile genetic elements
see transposable genetic elements (below).
genetic production potential
inherited productivity but still influenced by environmental risk factors.
genetically determined resistance to specified infectious agents.
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.
that portion of the phenotypic variance of a trait in a population which can be attributed to genetic difference amongst individuals.