Mapping of Deletions and Substitutions in Heteroduplex DNA Molecules of Bacteriophage Lambda by Electron Microscopy
Mapping of Deletions and Substitutions in Heteroduplex DNA Molecules of Bacteriophage Lambda by Electron Microscopy
复制标题
通过电子显微镜绘制噬菌体 Lambda 异源双链 DNA 分子中的缺失和取代图谱
DOI：
10.1126/science.163.3873.1343
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发表时间：
1969
期刊：
影响因子：
56.9
通讯作者：
H. Ris
中科院分区：
文献类型：
--
作者：
Barbara C. Westmoreland;W. Szybalski;H. Ris
异源双链 DNA 分子由大肠杆菌噬菌体 λ+ DNA 的一条链与 λ 缺失或取代突变体的互补 DNA 链退火组成，通过电子显微镜观察，可以对其他双链分子中非同源的未配对单链区域进行可视化以及精确测量和绘图。在 λb2 突变体中，λ+ DNA 分子的中央片段（13%）被删除。在杂交噬菌体 λi434 和 λi21 中，λ+ 基因组右臂的一段（5.5% 或 7.6% 至 9%）被噬菌体 434（3.3% 或噬菌体 21（4%）DNA）的相应免疫区域取代。λb5 突变体中的 b5 区域似乎与 i21 片段相同。根据这些数据，可以估计这些 λ 的大小和位置。该方法允许以迄今为止无法达到的精度制备病毒基因组的完整物理图谱。
Electron microscopy of heteroduplex DNA molecules, composed of one strand of Escherichia coli phage λ+ DNA annealed to the complementary DNA strand of a λ deletion or substitution mutant, permits visualization, as well as precise measurements and mapping, of the unpaired single-stranded regions of nonhomology in the otherwise double-stranded molecules. In the λb2 mutant, the central segment (13 percent) of the λ+ DNA molecule is shown to be deleted. In the hybrid phages λi434 and λi21 a segment of the right arm of the λ+ genome (5.5 or 7.6 to 9 percent) is replaced by the corresponding immunity regions of phage 434 (3.3 percent or phage 21 (4 percent) DNA. The b5 region in the λb5 mutant appears to be identical to the i21 segment. From these data it is possible to estimate the size and posiion of those λ genes which are replaced by the i434 and i21 segments. The method permits preparing complete physical maps of viral genomes with a precision heretofore unattainable.