Five polymorphic microsatellite VNTRs on the human X chromosome.
Five polymorphic microsatellite VNTRs on the human X chromosome.
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DOI：
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发表时间：
1990-04
影响因子：
9.8
通讯作者：
J. Luty;Z. Guo;H. Willard;D. Ledbetter;S. Ledbetter;M. Litt
中科院分区：
文献类型：
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作者：
J. Luty;Z. Guo;H. Willard;D. Ledbetter;S. Ledbetter;M. Litt
人类基因组包含约50,000个拷贝的穿插重复序列(dT.dG/dA.dC)n，其中n=约10-60。我们和其他人发现，其中几个重复序列在不同的个体中具有不同的长度，等位基因片段的大小相差2个碱基对的倍数。这些“微卫星”可变数目的串联重复序列(VNTRs)可以通过聚合酶链式反应(PCR)进行评分，使用独特的侧翼引物来扩增包含重复序列的区域，并在DNA测序凝胶上解析产物。由于在X染色体上发现的VNTRs很少，我们筛选了一个流动排序的X染色体特异微卫星基因组文库。大约25%的噬菌体克隆与聚(DT-DG).聚(DA-DC)探针杂交。在阳性噬菌体中存在的7个X连锁微卫星中，5个是多态的，3个同时具有8个或更多的等位基因，杂合度超过75%。用聚合酶链式反应从杂交细胞板中扩增基因组DNA，我们证实了这些VNTRs的X定位，并对其中4个进行了区域定位。第五个VNTR因其与人类多态中心DXS87的紧密连锁而被地区性定位。我们的结论是，无论是什么因素限制了X染色体上“经典”VNTRs和RFLP的出现，在微卫星VNTRs的情况下似乎并不起作用。
The human genome contains approximately 50,000 copies of an interspersed repeat with the sequence (dT.dG/dA.dC)n, where n = approximately 10-60. We and others have found that several of these repeats have variable lengths in different individuals, with allelic fragments varying in size by multiples of 2 bp. These "microsatellite" variable number of tandem repeats (VNTRs) may be scored by PCR, using unique flanking primers to amplify the repeat-containing regions and resolving the products on DNA sequencing gels. Since few VNTRs have been found on the X chromosome, we screened a flow-sorted X chromosome-specific genomic library for microsatellites. Approximately 25% of the phage clones hybridized to a poly (dT-dG).poly(dA-dC) probe. Of seven X-linked microsatellites present in positive phages, five are polymorphic and three have both eight or more alleles and heterozygosities exceeding 75%. Using PCR to amplify genomic DNAs from hybrid cell panels, we confirmed the X localization of these VNTRs and regionally mapped four of them. The fifth VNTR was regionally mapped by virtue of its tight linkage to DXS87 in Centre du Polymorphisme Humain families. We conclude that whatever factors limit the occurrence of "classical" VNTRs and RFLPs on the X chromosome do not appear to operate in the case of microsatellite VNTRs.