Chromosome disorder: An abnormal condition due to something unusual in an individual’s chromosomes. For example, Down syndrome is a chromosome disorder caused by the presence of an extra copy of chromosome 21, and Turner syndrome is most often due to the presence of only a single sex chromosome: one X chromosome.
- 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 […]
- Chromosome inversion
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 […]
- Chromosome inversion, pericentric
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.
- Chromosome map
Chromosome map: The chart of the linear array of genes on a chromosome. A chromosome map can also refer to the visual appearance of a chromosome when stained and examined under a microscope. Particularly important are visually distinct regions, called light and dark bands, which give each of the chromosomes a unique appearance. This feature […]