Moyzis R K, Torney D C, Meyne J, Buckingham J M, Wu J R, Burks C, Sirotkin K M, Goad W B
Genetics Group, Los Alamos National Laboratory, University of California, New Mexico 87545.
Genomics. 1989 Apr;4(3):273-89. doi: 10.1016/0888-7543(89)90331-5.
The distribution of interspersed repetitive DNA sequences in the human genome has been investigated, using a combination of biochemical, cytological, computational, and recombinant DNA approaches. "Low-resolution" biochemical experiments indicate that the general distribution of repetitive sequences in human DNA can be adequately described by models that assume a random spacing, with an average distance of 3 kb. A detailed "high-resolution" map of the repetitive sequence organization along 400 kb of cloned human DNA, including 150 kb of DNA fragments isolated for this study, is consistent with this general distribution pattern. However, a higher frequency of spacing distances greater than 9.5 kb was observed in this genomic DNA sample. While the overall repetitive sequence distribution is best described by models that assume a random distribution, an analysis of the distribution of Alu repetitive sequences appearing in the GenBank sequence database indicates that there are local domains with varying Alu placement densities. In situ hybridization to human metaphase chromosomes indicates that local density domains for Alu placement can be observed cytologically. Centric heterochromatin regions, in particular, are at least 50-fold underrepresented in Alu sequences. The observed distribution for repetitive sequences in human DNA is the expected result for sequences that transpose throughout the genome, with local regions of "preference" or "exclusion" for integration.
运用生化、细胞学、计算和重组DNA等多种方法，对人类基因组中散布的重复DNA序列的分布情况进行了研究。“低分辨率”生化实验表明，人类DNA中重复序列的总体分布可用假定随机间隔（平均距离为3 kb）的模型来充分描述。沿400 kb克隆人类DNA（包括为本研究分离的150 kb DNA片段）的重复序列组织的详细“高分辨率”图谱与这种总体分布模式一致。然而，在该基因组DNA样本中观察到大于9.5 kb的间隔距离出现频率更高。虽然总体重复序列分布最好用假定随机分布的模型来描述，但对GenBank序列数据库中出现的Alu重复序列分布的分析表明，存在Alu定位密度不同的局部区域。对人类中期染色体的原位杂交表明，在细胞学上可以观察到Alu定位的局部密度区域。特别是着丝粒异染色质区域，在Alu序列中的含量至少低50倍。人类DNA中重复序列的观察分布是在整个基因组中发生转座的序列的预期结果，存在整合的局部“偏好”或“排斥”区域。
