Chromosome duplication
Chromosome duplication: Part of a chromosome in duplicate. A particular kind of mutation involving the production of one or more copies of any piece of DNA, including sometimes a gene or even an entire chromosome.
A duplication is the opposite of a deletion.
Duplications have been important in the evolution of the human genome (and the genomes of many other organisms). Duplications typically arise from an event termed unequal crossing-over (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.
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Chromosome inversion: A condition in which a chromosome segment is clipped out, turned upside down, and reinserted back into the chromosome. A chromosome inversion can be inherited from one or both parents, or it may be a mutation that appears in a child whose family has no history of chromosome inversion. An inversion can be […]
- Chromosome inversion, paracentric
Chromosome inversion, paracentric: A type of chromosome rearrangement in which a chromosomal segment that does not include the centromere (and is therefore paracentric) is snipped out of a chromosome, inverted, and inserted back into the chromosome. The feature that makes it paracentric is that both breaks are on the same side of the centromere, so […]
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Chromosome inversion, pericentric: A basic type of chromosome rearrangement in which a segment that includes the centromere (and is therefore pericentric) is snipped out of a chromosome, inverted, and inserted back into the chromosome. The feature that makes it pericentric is that the breaks are on both sides of the centromere.
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