Chromosome-type aberrations

The nucleus of all eucariotic cells contains the carrier of the genetic information in the chromosomes. It is possible to visualize the chromosomes and analyze their number and pattern during a special period of cell division (the metaphase). Alterations from their normal shapes are observed as structural chromosome aberrations. These are chromosome type aberrations (terminal and interstitial deletions, dicentrics and rings), chromatid aberrations (gaps, breaks and exchanges) and sister chromatid exchanges. Spontanous frequencies of such chromosome... 

Figure 1. Total chromosome type aberration frequencies (sum of dicentrics, terminal and interstitial deletions) in the population of Badgastein.

Oya, Y, Yamamoto, K. Tonomura, A. (1986) The biological activity of hydrogen peroxide I. Induction of chromosome-type aberrations susceptible to inhibition by scavengers of hydroxyl radicals in human embryonic fibroblasts. Mutat. Res., 172, 245-253... 

Chromosome-type aberration The damage expressed in both sister chromatids at the same locus. 

Chromosome-type aberrations are induced when a compound acts in the Gi phase of the cell cycle. Chromatid-type aberrations are induced when a chemical acts in the S or G2 phase of the cell cycle. 

Chromosome-type aberrations are structural chromosome damages expressed as breakage, or breakage and reunion, of both chromatids at an identical site. 

The induction of structural chromosome aberrations is classified in two types, chromosome or chromatid aberrations. The majority of induced aberrations are of the chromatid-type, but chromosome-type aberrations also occur. Chromosomal mutations and related events are the cause of many human genetic diseases and there is evidence that chromosomal mutations and related events are involved in cancer development. 

Oya Y, Yamamoto K, Tonomura A The Biological Activity of Hydrogen Peroxide. 1. Induction of Chromosome-type Aberrations Susceptible to Inhibition by Scavangers of Hydroxyl Radicals in Human Embryonic Fibroblasts. Mutat. Res. 1986 172(3) 245-53. 

Comparisons of chromosome-type aberrations found by different authors in control... 

For practical purposes, the aberrations may be divided into three main types, viz, subchromatid-, chromatid-, and chromosome-type aberrations. 

In an aberration of the chromosome type, the two chromatids of a chromosome are broken or exchanged at the same loci. The chromosome-type aberration is believed to be induced in G, i.e., before duplication when the chromosomes are still single. It is produced by ionizing radiation and probably by chemicals such as streptonigrin (Kihlman, 1964 Kihlman and Odmark, 1965), phleomycin (Mattingly, 1967 Kihlman et al, 1967), and 8-ethoxycaffeine (Scott and Evans, 1964 Kihlman and Odmark, 1965). 

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