Ali S, Wallace R B
Department of Molecular Biochemistry, Beckman Research Institute of the City of Hope, Duarte, CA 91010.
Nucleic Acids Res. 1988 Sep 12;16(17):8487-96. doi: 10.1093/nar/16.17.8487.
In the human genome, short tandem repetitive (STR) DNA sequences often show restriction fragment length polymorphisms (RFLPs) due to variation in the number of copies of the repeat unit. For a subset of these sequences known as minisatellites or variable number tandem repeat loci (VNTR), it has been proposed that a homologous "core" sequence of 10-12 nucleotides is involved in the mechanism(s) generating the polymorphism. In our present study we have prepared oligonucleotide probes complementary to one or two repeat units of several VNTR loci. Under stringent hybridization and wash conditions these probes hybridize locus specifically thus allowing the evaluation of the intrinsic polymorphism of individual loci. Our results indicate that not all of the loci having STR DNA sequences are polymorphic despite the fact that they share the "core" sequence. This suggests that more than the DNA sequence of the locus is involved in the mechanism(s) generating the polymorphism.
在人类基因组中，短串联重复（STR）DNA序列常常因重复单元拷贝数的变化而呈现限制性片段长度多态性（RFLP）。对于这些序列中的一个子集，即微卫星或可变数目串联重复序列位点（VNTR），有人提出，一个10 - 12个核苷酸的同源“核心”序列参与了产生多态性的机制。在我们目前的研究中，我们制备了与几个VNTR位点的一个或两个重复单元互补的寡核苷酸探针。在严格的杂交和洗涤条件下，这些探针可特异性地与位点杂交，从而能够评估各个位点的内在多态性。我们的结果表明，尽管具有STR DNA序列的位点共享“核心”序列，但并非所有这些位点都是多态性的。这表明，产生多态性的机制所涉及的不仅仅是位点的DNA序列。
