Ellard S, Parry E M, Parry J M
School of Biological Sciences, University of Wales, Singleton Park, Swansea, United Kingdom.
Environ Mol Mutagen. 1995;26(1):44-54. doi: 10.1002/em.2850260107.
Exchange aberrations induced by bleomycin were identified by multicolour fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 2, and 3. The frequency and distribution of aberration types were compared to conventional metaphase analysis of Giemsa-stained chromosomes from the same human lymphocyte cultures. The total percentage of exchanges detectable by painting three pairs of chromosomes with separate colours was calculated as 40%. Giemsa staining revealed predominantly asymmetric chromosome exchanges, which are expected to comprise 50% of the total induced exchanges. Genomic exchange frequencies were, therefore, determined by multiplying the observed frequencies from FISH analysis by 2.5 and the number of asymmetric exchanges identified in Giemsa-stained slides by 2.0. By these calculations, the genomic exchange frequency calculated from chromosome painting exceeded that estimated by Giemsa-staining. This difference was due to the identification by chromosome painting of a unique class of cells in which chromosomes had undergone complex exchanges (nonreciprocal exchanges involving multiple mutual sites). The percentage of cells exhibiting exchanges was similar for both methods.
使用针对1号、2号和3号染色体的探针，通过多色荧光原位杂交（FISH）鉴定博来霉素诱导的交换畸变。将畸变类型的频率和分布与来自相同人类淋巴细胞培养物的吉姆萨染色染色体的传统中期分析进行比较。用单独颜色对三对染色体进行涂染可检测到的交换的总百分比计算为40%。吉姆萨染色主要显示不对称染色体交换，预计其占诱导交换总数的50%。因此，基因组交换频率通过将FISH分析中观察到的频率乘以2.5来确定，而在吉姆萨染色载玻片中鉴定出的不对称交换数量则乘以2.0。通过这些计算，染色体涂染计算出的基因组交换频率超过了吉姆萨染色估计的频率。这种差异是由于染色体涂染鉴定出了一类独特的细胞，其中染色体经历了复杂交换（涉及多个相互位点的非相互交换）。两种方法显示发生交换的细胞百分比相似。
