- Part of a chromosome in duplicate, a particular kind of mutation (change) involving the production of one or more copies of any piece of DNA, including a gene or even an entire chromosome. Duplications typically arise from an event termed unequal crossing-over (a kind of recombination) that occurs between misaligned homologous chromosomes during meiosis (germ cell formation). The chance of this event happening is a function of the degree of sharing of repetitive elements between two chromosomes. The recombination products of such an event are a duplication at the site of the exchange and a reciprocal deletion. A remarkable class of duplications in which the duplicated region has popped up far away from home base has also been discovered. Duplications have been important in the evolution of the human genome (and the evolution of the genomes of many other organisms). A duplication is the opposite of a deletion.
* * *1. A doubling. SEE ALSO: reduplication. 2. Inclusion of two copies of the same genetic material in a genome; an important step in diversification of genomes, as in the evolution of the (nonallelic) hemoglobin chains from a common ancestor. SYN: gene d.. [L. duplicatio, a doubling, fr. duplico, to double]- d. of chromosomes a chromosome aberration resulting from unequal crossing over or exchange of segments between two homologous chromosomes; one chromosome of the pair loses a small segment, while the other gains this segment; the chromosome gaining the segment has undergone d. while its homologue has undergone deletion. See hemoglobin Lepore.
* * *1) the act or process of duplicating: the quality or state of being duplicated2) a part of a chromosome in which the genetic material is repeated also the process of forming a duplication
* * *du·pli·ca·tion (doo″plĭ-kaґshən) [L. duplicatio doubling] 1. the act or process of doubling, or the state of being doubled. 2. in genetics, the presence in the genome of additional genetic material (a chromosome or segment of one, a gene or part of one). See also repeat. 3. a doubling of parts, which may be connected at some point, the extra part may be a mirror image of the other. See also conjoined twins, under twin. Called also duplicitas and reduplication.
Medical dictionary. 2011.