Liehr T, Weise A, Heller A, Starke H, Mrasek K, Kuechler A, Weier H-U G, Claussen U
Institute of Human Genetics and Anthropology, University of Jena, Jena, Germany.
Cytogenet Genome Res. 2002;97(1-2):43-50. doi: 10.1159/000064043.
Multicolor chromosome banding (MCB) allows the delineation of chromosomal regions with a resolution of a few megabasepairs, i.e., slightly below the size of most visible chromosome bands. Based on the hybridization of overlapping region-specific probe libraries, chromosomal subregions are hybridized with probes that fluoresce in distinct wavelength intervals, so they can be assigned predefined pseudo-colors during the digital imaging and visualization process. The present study demonstrates how MCB patterns can be produced by region-specific microdissection derived (mcd) libraries as well as collections of yeast or bacterial artificial chromosomes (YACs and BACs, respectively). We compared the efficiency of an mcd library based approach with the hybridization of collections of locus-specific probes (LSP) for fluorescent banding of three rather differently sized human chromosomes, i.e., chromosomes 2, 13, and 22. The LSP sets were comprised of 107 probes specific for chromosome 2, 82 probes for chromosome 13, and 31 probes for chromosome 22. The results demonstrated a more homogeneous coverage of chromosomes and thus, more desirable banding patterns using the microdissection library-based MCB. This may be related to the observation that chromosomes are difficult to cover completely with YAC and/or BAC clones as single-color fluorescence in situ hybridization (FISH) experiments showed. Mcd libraries, on the other hand, provide high complexity probes that work well as region-specific paints, but do not readily allow positioning of breakpoints on genetic or physical maps as required for the positional cloning of genes. Thus, combinations of mcd libraries and locus-specific large insert DNA probes appear to be the most efficient tools for high-resolution cytogenetic analyses.
多色染色体显带（MCB）能够以几个兆碱基对的分辨率描绘染色体区域，即略低于大多数可见染色体带的大小。基于重叠区域特异性探针文库的杂交，染色体亚区域与在不同波长区间发出荧光的探针杂交，因此在数字成像和可视化过程中可以为它们指定预定义的伪颜色。本研究展示了如何通过区域特异性显微切割衍生（mcd）文库以及酵母人工染色体或细菌人工染色体（分别为YAC和BAC）集合来产生MCB模式。我们比较了基于mcd文库的方法与位点特异性探针（LSP）集合杂交用于对三条大小差异较大的人类染色体（即2号、13号和22号染色体）进行荧光显带的效率。LSP集由针对2号染色体的107个探针、针对13号染色体的82个探针和针对22号染色体的31个探针组成。结果表明，基于显微切割文库的MCB对染色体的覆盖更均匀，因此显带模式更理想。这可能与以下观察结果有关：如单色荧光原位杂交（FISH）实验所示，用YAC和/或BAC克隆很难完全覆盖染色体。另一方面，mcd文库提供了高复杂性的探针，作为区域特异性描绘效果良好，但不容易像基因定位克隆所需的那样在遗传或物理图谱上定位断点。因此，mcd文库和位点特异性大插入DNA探针的组合似乎是高分辨率细胞遗传学分析最有效的工具。
