Yu S, Pritchard M, Kremer E, Lynch M, Nancarrow J, Baker E, Holman K, Mulley J C, Warren S T, Schlessinger D
Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, South Australia.
Science. 1991 May 24;252(5009):1179-81. doi: 10.1126/science.252.5009.1179.
DNA sequences have been located at the fragile X site by in situ hybridization and by the mapping of breakpoints in two somatic cell hybrids that were constructed to break at the fragile site. These hybrids were found to have breakpoints in a common 5-kilobase Eco RI restriction fragment. When this fragment was used as a probe on the chromosomal DNA of normal and fragile X genotype individuals, alterations in the mobility of the sequences detected by the probe were found only in fragile X genotype DNA. These sequences were of an increased size in all fragile X individuals and varied within families, indicating that the region was unstable. This probe provides a means with which to analyze fragile X pedigrees and is a diagnostic reagent for the fragile X genotype.
通过原位杂交以及对两个构建为在脆性X位点断裂的体细胞杂种中的断点进行定位，已确定了脆性X位点的DNA序列。发现这些杂种在一个共同的5千碱基埃克RI限制片段中有断点。当将该片段用作正常和脆性X基因型个体染色体DNA的探针时，仅在脆性X基因型DNA中发现探针检测到的序列迁移率发生改变。在所有脆性X个体中，这些序列的大小都增加了，并且在家族内部有所不同，这表明该区域不稳定。该探针提供了一种分析脆性X谱系的方法，并且是脆性X基因型的诊断试剂。
