FINE-STRUCTURE MAPPING OF HUMAN CHROMOSOME 4

遗传学家过去50年的目标一直是构建一种 人类基因组的高分辨率地图。早期研究完全依赖于 减数分裂作图方法，这些方法提供了低分辨率的 染色体。限制片段长度多态的使用有 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，并定位与 遗传性疾病。然而，这些减数分裂的分辨率极限 MAP大约有几百万个碱基对。另一方面 另一方面，分子克隆技术的发展为 强大的工具来检查较小的DNA，范围在数千 碱基对。然而，完整的高分辨率地图即使是 人类最小的染色体还没有被构建，因为它们 巨大的体型。体细胞遗传学的最新进展--大DNA 电泳法和原位杂交法填补了这一空白 在这些遗传和物理图谱之间，允许绘制区域图 大小范围为几百千巴(Kb)的DNA。他们 这里提出的研究将建立一个协调的基因组中心，以安装一个 有组织地构建了人类4号染色体的详细图谱。 这些新地图技术的结合，包括最近- 开发了体细胞程序，称为辐射杂交(RH)作图，以及 遗传和分子克隆方法将被用来描绘一张地图 大小范围为几百kb。染色体最初将是 分成10个不同的隔间，每个隔间约20 MBP。 每个隔间约40个DNA探针将通过RH图谱进行排序， 然后对这40个区域进行大插入克隆，以产生物理 有序DNA克隆图。多态DNA标记将产生于 这些有序克隆产生了一张高分辨率的遗传连锁图谱。 原位、RH、物理和遗传图谱的伴随构建 将提供一种强大的手段来制作一张全面的地图 染色体效率高。

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.