FINE-STRUCTURE MAPPING OF HUMAN CHROMOSOME 4

在过去的50年里，遗传学家的一个目标是构建一个 高分辨率的人类基因组图谱 早期的研究完全依赖于 减数分裂作图方法，它提供了低分辨率的地图， 染色体 限制性片段长度多态性的使用 使提高分辨率和构建遗传连锁成为可能 所有23条人类染色体的图谱，并定位负责 遗传性疾病。 然而，这些减数分裂的分辨率的限制 图是几百万个碱基对（Mbp）的量级。 另 另一方面，分子克隆技术的发展提供了 强大的工具来检查更小尺寸的DNA，在数千个范围内， 的碱基对。 然而，即使是完整的高分辨率地图 人类最小的染色体还没有被构建出来， 巨大的尺寸。 体细胞遗传学的最新进展，大DNA 电泳和原位杂交有助于填补差距 在这些遗传和物理图谱之间， DNA的大小范围为几百个碱基对（kb）。 他们 这里提出的研究将建立一个协调的基因组中心， 有组织地努力构建人类4号染色体的详细图谱。 一 这些新的测绘技术的组合，包括最近- 开发了称为辐射杂交（RH）作图的体细胞程序， 基因和分子克隆方法将用于描绘一个地图， 大小范围为几百kb。 染色体最初将 分成10个不同的隔室，每个隔室大约20 Mbp。 每个隔室中约40个DNA探针将通过RH作图排序， 然后对这40个区域进行大插入克隆， 有序DNA克隆图。 多态性DNA标记将从 这些克隆产生了高分辨率的遗传连锁图。 同时构建原位、相对湿度、物理和遗传图谱 将提供一个强大的手段，以产生一个全面的地图， 染色体有效。

A goal of geneticists for the last fifty years has been to construct a high-resolution map of the human genome. Early studies relied entirely on meiotic mapping methods, which provided low-resolution maps of the chromosomes. The use of restriction fragment length polymorphisms has made it possible to improve this resolution and construct genetic linkage maps of all 23 human chromosomes and to localize genes responsible for inherited diseases. However, the limit of resolution of these meiotic maps is on the order of a few million base pairs (Mbp). On the other hand, the development of molecular cloning techniques has provided powerful tools to examine DNA of smaller size, in the range of thousands of base pairs. However, complete high-resolution maps of even the smallest human chromosomes have not yet been constructed because of their enormous size. Recent advances in somatic cell genetics, large DNA electrophoresis, and in situ hybridization have helped to fill the gap between these genetic and physical maps, allowing the mapping of regions of DNA in the size range of several hundred kilobasepairs (kb). They study proposed here will establish a coordinated Genome Center to mount an organized effort to construct a detailed map of human chromosome 4. A combination of these new mapping technologies, including a recently- developed somatic cell procedure called Radiation Hybrid (RH) mapping, and genetic and molecular cloning methods will be used to delineate a map in the size range of several hundred kb. The chromosome will initially be broken into ten different compartments of approximately 20 Mbp each. About 40 DNA probes in each compartment will be ordered by RH mapping, followed by large-insert cloning of these 40 regions to produce a physical map of ordered DNA clones. Polymorphic DNA markers will be generated from these ordered clones to produce a high resolution genetic linkage map. The concomitant construction of in situ, RH, physical and genetic maps will provide a powerful means to produce a comprehensive map of the chromosome efficiently.