EFFICIENT GENE MAPPING BY WHOLE GENOME MISMATCH SCANNING

这项拟议工作的目标是开发一种全新的方法来 快速直接绘制按血统划分的遗传同一性区域 两个亲缘关系的人，只使用这两个人的DNA样本。 该方法旨在允许简单而强大但目前 不切实际的“受影响亲属对”映射策略将被投入 练习一下。提出的方法的主要优点是：1.没有 其他家庭成员需要检查，没有血统信息需要检查 必填项。2.不需要位点特异性探针。3.整个基因 地图在单个程序中以高分辨率进行测量，而不是 通过每隔一段时间对多态基因座进行多重离散分析 在整个基因图谱中。该方法利用了以下事实 (至少在近亲繁殖的西欧人或美国人中)任何两个等位基因 不是从共同的最近祖先继承的序列具有单一 平均每几百(约300)个基准点的基差。在……里面 换句话说，对于任意一对亲戚来说，大约有10-7个 每个单倍体基因组具有潜在信息量的“序列多态”。这个 所提出的方法旨在提供一种实用的方法来开发这一巨大的 基因图谱的信息来源。该方法包括四个步骤： 1.从两个近缘个体中提取基因组DNA。2.准备和 从每个个体中分离出含有一条链的杂交DNA分子。 3.选择无错配的DNA杂交种 成千上万的碱基对，因此很可能代表 通过血统遗传的同一性。4.使用由此产生的大型、异类 一群完美匹配的DNA杂交体作为探针的模板， 最初用于中期染色体的原位杂交，以鉴定 两个被测试的序列之间通过下降而相同的地图位置 个人。有足够大的受影响亲属的集合 对，遗传整合的频率在图谱位置(S) 决定性状的基因(S)将超过预期的偶然出现。在……里面 一种罕见的性状由一对显性等位基因唯一决定的情况 单基因(如von Recklinhausen‘s神经纤维瘤病)，10对 通常情况下，拥有相同特征的亲属就足以定位基因 到基因组的一个10兆碱基区域。大多数技术支持 实施这一方法的障碍实际上已经被 以前的工人，在其他情况下。因此，虽然建议的 现有技术在基因定位中的串联和适应 代表了与以前的地图策略的根本背离，不 援引了根本性的技术突破。一种密切相关的方法 仅利用一个或几个受影响的DNA定位稀有隐性性状 个人也将接受测试。

The goal of the proposed work is to develop a radically new method for rapid direct mapping of the regions of genetic identity-by-descent between two related individuals, using only DNA samples from the two individuals. The method is intended to allow the simple and powerful but presently impractical "affected relative pair" mapping strategy to be put into practice. The principal advantages of the proposed method are: 1. No other family members need to be examined, and no pedigree information is required. 2. No locus-specific probes are required. 3. The entire genetic map is surveyed at high resolution in a single procedure, rather than through multiple discrete analyses of polymorphic loci at intervals throughout the genetic map. The method takes advantage of the fact that (at least in an outbred Western European or US population) any two allelic sequences that are not inherited from a common recent ancestor have single base differences on average every few hundred (about 300) basepairs. In other words, for an arbitrary pair of relatives, there are around 10-7 potentially informative "sequence polymorphisms" per haploid genome. The proposed method is designed to provide a practical way to exploit this vast source of information for gene mapping. The method involves four steps: 1. Preparing genomic DNA from two related individuals. 2. Preparing and isolating hybrid DNA molecules containing one strand from each individual. 3. Selecting those DNA hybrids that are free of mismatches over many thousands of base-pairs, and therefore very likely to represent sites of genetic identity by descent. 4. Using the resulting large, heterogeneous pool of perfectly, matched DNA hybrids as the template for probes, initially for in situ hybridization to metaphase chromosomes, to identify the map locations of sequences identical by descent between the two tested individuals. With a sufficiently large collection of affected relative pairs, the frequency of genetic concordance at the map position(s) of the trait-determining gene(s) will exceed that expected to occur by chance. In the case of a rare trait uniquely determined by a dominant allele of a single gene (e.g., von Recklinhausen's neurofibromatosis), 10 pairs of relatives sharing the trait would generally be sufficient to map the gene to a single 10 megabase region of the genome. Most of the technical obstacles to implementation of this approach have actually been overcome by previous workers, in other contexts. Thus, while the proposed concatenation and adaptation of available techniques to gene mapping represents a fundamental departure from previous mapping strategies, no fundamental technical breakthroughs are invoked. A closely-related method for mapping rare recessive traits using DNA from only one or a few affected individuals will also be tested.