Analysis of transgenerational effects on DNA copy number aberrations in male mice exposed to continuous 0.05mGy/day gamma-rays for 400 days (Primary screening for 0.05mGyL familly).. Analysis of transgenerational effects on DNA copy number aberrations in male mice exposed to continuous 0.05mGy/day gamma-rays for 400 days (Primary screening for 0.05mGyL 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/6JNrs male mice were exposed to LDR gamma-rays (0.05 mGy/day) for 400 days (total dose: 20 mGy) from 8 weeks of age. Progeny from 0.05 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 (0.05 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. Overall design: Two-condition experiment, C57BL/6JNrs tail tissue non-irradiated male (0.05 mGyLM), female (0.05 mGyLF) and their progenies (0.05 mGyL1 to 0.05 mGyL6) vs. reference male mouse. We irradiated and non-irradiated male mice (C57BL/6JNrs) for 400 days and cross to non- irradiated female mice (C57BL/6JNrs) and got F1 mice. After they dead the DNA were prepared from their tails. At first, primary screening using １M oligo-microarray was performed. The array was mounted autosomal fragment at intervals of an average about 2kb. Two-condition experiment, mice tail tissue irradiated or non-irradiated male, female and their progenies 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.

持续低剂量率γ射线照射（continuous low dose-rate gamma-ray irradiation, LDR）的跨代效应尚未得到充分研究。近年来DNA技术的进步使得我们能够在分子层面开展全基因组检测。本研究采用了其中一项名为寡核苷酸微阵列比较基因组杂交（oligo-microarray comparative genome hybridization, CGH）的技术，探究了跨代DNA拷贝数变异（DNA copy number aberrations, CNAs）的变化情况。
将8周龄的C57BL/6JNrs雄性小鼠以0.05 mGy/天的剂量接受持续400天的LDR γ射线照射（总剂量为20 mGy）。结果显示，照射组雄性小鼠的子代基因组变异频率显著低于未照射组雄性小鼠的子代。
本研究通过对比15个接受0.05 mGy/天LDR γ射线照射的雄性家系与25个未照射雄性家系的亲子样本，对新发突变（De novo mutation）进行了探究，本实验属于初步筛选阶段。本研究由日本青森县政府委托开展。
实验设计：采用双条件对照实验，以C57BL/6JNrs小鼠尾部组织的未照射雄性（0.05 mGyLM）、雌性（0.05 mGyLF）及其子代（0.05 mGyL1至0.05 mGyL6）作为实验组，以同批次实验用的雄性小鼠作为参考对照。
我们对C57BL/6JNrs雄性小鼠进行为期400天的照射与未照射处理，随后与未照射的雌性C57BL/6JNrs小鼠交配，获得F1代小鼠。待小鼠处死后，提取其尾部组织的DNA。首先使用1M寡核苷酸微阵列开展初步筛选：该芯片以平均约2kb的间隔排布常染色体片段。同样采用双条件对照实验，以照射或未照射的雄性、雌性小鼠及其子代的尾部组织为样本，与同批次实验用的雄性参考小鼠进行对照。该参考雄性小鼠来自本实验所用的同一繁殖群。通过交替使用Cy3与Cy5两种荧光标记物开展两轮CGH实验，筛选出存在拷贝数变异的探针，并确定这些探针的染色体定位。对存在变异探针的相邻区域设计高密度探针。将单个家系的候选探针整合至单张4×244k或8×60k寡核苷酸微阵列中，开展第二轮筛选：通过Cy3与Cy5标记分别检测侧翼探针的变异情况，再次确定探针的染色体定位。
最终，采用TaqMan®拷贝数检测试剂盒（TaqMan® Copy Number Assays）对候选突变进行验证。