An interpretation of the origin of subchromatid aberrations and chromosome stickiness as a category of chromatid aberrations

Abstract

From a study of the effect of X irradiation on meiosis of the grasshopper Stethophyma grossum spermatocytes, it was deduced that the so‐called “subchromatid aberrations” and the other effects which are generally referred to as physiological effects (i.e., stickiness, clumping and erosion of chromosomes) are in reality chromatid aberrations. The appearance of these aberrations results from the induction of breaks and exchanges in chromosomes during the prophase contraction, in which the chromatin fibers are held together in a three‐dimensional organisation and cannot unfold. The origin of these kinds of aberrations can be explained on the basis of the folded fiber model of the chromosome. During meiosis in many organisms, a diffuse stage resembling the interphase nucleus (between pachytene and diplotene) is known to exist. If the diffuse stage is irradiated 48 hours or more before fixation with 500 R of X‐rays, the diplotene folding is only partially realized and meiosis is blocked after the formation of an irregular network of chromatin fibers. The results indicate that although the diffuse stage looks like a regression to an interphase stage, the chromosome organisation is likely to be different. Irradiation with the same dose at a later stage (26 hours or less before fixation) does not prevent the course of meiosis.

Cadmium localization and its toxic effects on root tips of barley

“…The sticky chromosomes were often observed in the root tip cells exposed to high (50 to 100 µM) Cd concentrations, which reflects high toxic effects, usually of an irreversible type, and probably leads to cell death. The sticky chromosome arises from improper folding of the chromosome fibre into single chromatids and chromosomes become attached to each other by means of subchromatid bridges (McGill et al, 1974;Klásterá et al, 1976). The data presented here clearly demonstrated that cadmium had a toxic effect on root growth of barley when compared with the control, which is in good agreement with the findings by Zhang et al (2009) and Shi et al (2014).…”

Protective roles of exogenous polyamines on chromosomal aberrations in Hordeum vulgare exposed to salinity

“…2). Laggards and precocious movement of chromosomes could be the result from the failure of spindle apparatus to organize in normal way (Patil & Bhat 1992), and chromosomes encircled may result from improper folding of the chromatin fibers (Klasterska et al 1976). Equatorial plate divided to two and disorderly anaphase may result from unequal distribution of chromosome and spindle dysfunction.…”

The Effects of <i>Aloe vera</i> L. Leaf Extract on Some Physiological and Cytogenetical Parameters in <i>Allium cepa</i> L. Seeds Germinated under Salt Stress

“…The formations of micronuclei are likely the consequence of vagrant chromosomes and fragments (Briand and Kapoor 1989). Sticky chromosomes may result from improper folding of the chromatin fibres (Klasterska et al 1976). Some researchers reported that the stickiness reflects a highly toxic effect on chromatin (Fiskesjö and Levan 1993).…”