Analysis of transgenerational effects on DNA copy number aberrations in male mice exposed to continuous 1mGy/day gamma-rays for 400 days (Primary screening for 1mGyK familly).

Transgenerational effects of continuous low dose-rate (LDR) gamma-ray irradiation have not been well studied. Recent advances in DNA technology enabled us to examine a whole genome at molecular level. Here we adopted one of these techniques called oligo-microarray comparative genome hybridization (CGH) and studied trans-generational effects on DNA copy number aberrations (CNAs). C57BL/6J male mice were exposed to LDR gamma-rays (1 mGy/day) for 400 days (total dose: 400 mGy) from 8 weeks of age. Progeny from 1 mGy/day irradiated mice had significantly lower frequencies of genomic aberrations than the progeny of non-irradiated mice.This study investigated the De novo mutation by comparing the parents and children using 15 LDR gamma-rays (1 mGy/day) irradiated male family and 25 non irradiated male family. This is a primary screening. This study was performed under contract with the Aomori Prefectural Government, Japan. Two-condition experiment, C57 Black/J6Nrs tail tissue non-irradiated male (1mGyKM), female (1mGyKF) and their progenies (1mGyK1 to 1mGyK7) vs. reference male mouse. This reference male mouse was from the same colony used in this experiment. Twice by changing the labeling color Cy3 and Cy5, performed CGH and extracting probes showed either aberration. Identification the chromosomal location of the probe. Probes adjacent to the probe with aberration were set at high density. The candidate probes in one family was designed in a single 4x 244k or 8x 60k oligo-microarray and performed secondary screening. Extracting the flanking probes showed either aberration when labeled with Cy3 and Cy5 and identification the chromosomal location of the probe. Finally, we performed TaqMan® Copy Number Assays to verify the mutations.