Boylan K B, Ayres T M, Popko B, Takahashi N, Hood L E, Prusiner S B
Departments of Neurology, University of California, San Francisco 94143.
Genomics. 1990 Jan;6(1):16-22. doi: 10.1016/0888-7543(90)90443-x.
DNA 5' to the human myelin basic protein (MBP) gene, mapped to 18q22----qter, is known to manifest multiallelic DNA length variation with heterozygosity of at least 45%. Isolation of genomic DNA containing the MBP gene first exon and its 5' flanking region reveals that this polymorphism arises from a 994-bp region of the diverged tandem repeat (TGGA)249. This sequence is located from 1082 to 2075 bp upstream of the MBP initiator methionine. The repetitive sequence is 18% diverged from (TGGA)249 and from analysis of higher order subsequence reiterations appears to have undergone extensive recombination. The pattern of higher order repetition suggests that multiple crossover and gene conversion events have occurred within a 1.0-kb region. Molecular clones of this sequence represent essentially the longest allelic form of this region seen in Southern transfer analysis. This repetitive DNA is similar to a sequence 5' to the human myoglobin gene.
定位于18q22----qter的人髓鞘碱性蛋白（MBP）基因5'端的DNA，已知表现出多等位基因DNA长度变异，杂合度至少为45%。包含MBP基因第一外显子及其5'侧翼区域的基因组DNA的分离表明，这种多态性源于发散串联重复序列（TGGA）249的一个994 bp区域。该序列位于MBP起始甲硫氨酸上游1082至2075 bp处。该重复序列与（TGGA）249有18%的差异，并且从高阶子序列重复分析来看，似乎经历了广泛的重组。高阶重复模式表明，在一个1.0 kb的区域内发生了多次交叉和基因转换事件。该序列的分子克隆基本上代表了在Southern印迹分析中看到的该区域最长的等位基因形式。这种重复DNA类似于人肌红蛋白基因5'端的一个序列。
