High prevalence of chromosome 10 rearrangements in human lymphocytes afterin vitro X-ray irradiation

Purpose: To evaluate the chromosome symmetric or asymmetric rearrangement ( CR) frequency for chromosome 10 compared to chromosomes 1 and 3 induced in vitro in human lymphocytes by low doses of X-rays. Materials and methods: Blood samples obtained from three young and healthy, volounteers were irradiated in GO with 0.25, 0.50 and 1 Gy X-rays. Chromos ome painting analysis was used on preparations of peripheral lymphocytes fo r the identification of CR. Results: It was found that radiation-induced CR levels were nonrandomly dis tributed among the three painted chromosomes. Chromosome 10 CR frequencies were significantly greater than those involving chromosomes 1 (at all the d oses tested) or 3 (at 0.25 and 1 Gy), with frequency ratios ranging from 2. 2 to 5.2. Conclusions: In comparison to chromosomes 1 and 3, chromosome 10 appeared t o be involved in exchanging at a significantly greater extent than expected according to its DNA content.