REFINEMENT OF THE YEAST PHYSICAL MAP

实验室酵母Saccharomyces cerevisiae的物理图谱 将通过进行更高分辨率的分析来改进， 提供与遗传图谱的更广泛的交叉相关， 提高配套馆藏质量 lambda克隆，并表征残留未克隆的原因 序列的 在单独支持的项目中， 建立一个连续的自然地图， 15 Mb（兆碱基对）酵母基因组，分辨率为3 kb （酶对）。 在本报告已经完成的工作的基础上， 长期项目，机会是十一月提供完善 在完成部分的海洋评估报告的同时， 正在建立连接。 通过使用间接末端标记， 部分消化技术，由高分辨率 可实现使用场反转凝胶电泳，映射 将从目前的依赖于单一的 限制酶消化，到用几种酶作图， 以每3 kb一次至每30 kb一次的频率裂解。 与遗传图谱的交叉相关程度， 目前基于50个遗传位点，将扩展到包括 大约200个位点。 此外，携带的一般方法 基于直接互补的功能性“染色体行走” 在λ克隆和酵母突变之间， 开发 通过加强物质和 基因图谱是交叉相关的，将有可能测试 假设重组的热点和冷点只产生 对减数分裂总频率的贡献很小 在酵母中重组。为了方便地图的完善， 使所有人都能容易地访问支持克隆集合 研究人员，一个大约1000个λ克隆的子集： 跨度酵母基因组将从整个集合中选择 5500个克隆人 这个子集中的克隆体将重新生长，重新- 分析，并储存在高滴度;在过去的基础上 经验，这些步骤被认为是必要的，以确保 永久提供高质量的主克隆集合 质量. 最后，分析了在联合国系统内存在剩余差距的主要原因， 将通过分析建立初始克隆收集 使用直接基因组分析和替代方法的代表性病例 克隆技术

The physical map of the laboratory yeast Saccharomyces cerevisiae will be refined by carrying the analysis to higher resolution, providing more extensive cross correlation with the genetic map, improving the quality of the supporting collection of overlapping lambda clones, and characterizing the reasons for residual uncloned sequences. In a separately supported project, work is well advanced on the establishment of a continuous physical map of the 15 Mb (megabase pair) yeast genome with a resolution of 3 kb (kilobase pairs). On the basis of work already completed in this long-term project, the opportunity is nov available to refine the completed portions of the mar at the same time that its final connectivity is being established. By using indirect-end-label, partial-digestion techniques, facilitated by the high resolution achievable using field-inversion gel electrophoresis, the mapping will be extended from its current dependence on a single restriction-enzyme digestion, to mapping with several enzymes that cleave at frequencies ranging from once per 3 kb to once per 30 kb. The extent of cross-correlation with the genetic map, which is presently based on 50 genetic loci, will be extended to include approximately 200 loci. Furthermore, a general method of carrying out functional "chromosome walks," based on direct complementation between the lambda clones and yeast mutations, will also be developed. By enhancing the extent to which the physical and genetic maps are cross-correlated, it will be possible to test the hypothesis that recombinational hot and cold spots make only a small contribution to the overall frequency of meiotic recombination in yeast. To facilitate the refinement of the map and make the supporting clone collection readily accessible to all investigators, a subset of approximately 1000 lambda clones :ha: span the yeast genome will be selected from the overall collection of 5500 clones. The clones in this subset will be regrown, re- analyzed, and stored at high titer; on the basis of past experience, these steps are deemed necessary to assure the permanent availability of a master clone collection of high quality. Finally, the major reasons for residual gaps in the initial clone collection will be established by analyzing representative cases using direct genomic analysis and alternative cloning techniques.