Non-proportional involvement of Chinese hamster chromosomes 3, 4, 8 and 9 in X-ray-induced chromosomal aberrations.

PURPOSE: To study by fluorescence in situ hybridization (FISH) the involvement of Chinese hamster chromosomes 3, 4, 8, and 9, and their separate chromosome arms in X-ray-induced aberrations.

MATERIALS AND

METHODS

Male embryonic primary cells of Chinese hamster were used and metaphases were collected and scored at 20 h after confluent cells were exposed to 1 and 4 Gy X-rays. The frequencies and types of chromosomal aberrations involving chromosomes 3, 4, 8, and 9 were studied by FISH using arm-specific painting probes. Proportional distribution of the induced aberrations was tested on the basis of the relative lengths of chromosomes or chromosome arms studied.

RESULTS

A non-proportional distribution of breaks, colour junctions as well as apparently simple dicentrics and translocations among the chromosomes studied was observed in the 4 Gy group. In general, chromosome 3 was less involved than expected and chromosome 8 was more involved than expected, and chromosomes 4 and 9 were involved as expected. A non-proportional involvement of arms in breaks, colour junctions and apparently simple dicentrics was also observed. The short arm of chromosome 3 was more involved in breaks and colour junctions than expected. The long arm of chromosome 4 was more involved in dicentrics than expected.

CONCLUSIONS

Results of this study indicate a non-proportional involvement of Chinese hamster chromosomes 3, 4, 8 and 9 as well as their arms in different types of aberrations following irradiation.