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 that the centromere is not involved in the rearrangement.
- 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 […]
- Chromosome, acentric
Chromosome, acentric: A fragment of a chromosome that lacks a centromere, so that the chromosome is lost when the cell divides.
- Chromosome, acrocentric
Chromosome, acrocentric: A chromosome that has its centromere located near one end of the chromosome. Humans have five pairs of acrocentric chromosomes. Down syndrome is due to an extra acrocentric chromosome (chromosome 21).
- Chromosome, dicentric
Chromosome, dicentric: A chromosome that is abnormal in that it has two centromeres rather than one. Because the centromere is essential for chromosome division, a dicentric chromosome is pulled in opposite directions when the cell divides. This causes the chromosome to form a bridge and then break and be unstable.