mBAND and mFISH analysis of chromosomal aberrations and breakpoint distribution in chromosome 1 of AG01522 human fibroblasts that were exposed to radiation of different qualities

In addition, by means of mBAND analysis, the distribution of radiation-induced breakpoints along chromosome 1 was analyzed and compared with the expected distributions of the breaks. The expected values were calculated assuming a random distribution of the breakpoints. The data indicate that, irrespective of the radiation that was used, the breakpoints were non-randomly distributed along chromosome 1. In particular, breaks in the pericentromeric region were encountered at a higher frequency than expected. A deeper analysis revealed that breaks were not located in the constitutive heterochromatin (G-bands 1p11/1q11 and 1q12), but rather in a region comprised between 1p11.2 and 1p22.1, which includes G-light and G-dark bands.