EVOLUTIONARY GENETICS OF DNA REPAIR AND RECOMBINATION

我们的长期目标是确定DNA修复在 重组的进化。通过研究两者之间的关系 重组到基因修复，我们希望推进 理解我们认为是两个相关的问题。第一, 生命系统是如何进化来应对 会导致基因损伤，从而导致癌症的物质。第二，是 重组的进化功能问题。这个 建议的工作将在真细菌枯草杆菌中进行测试 自然遗传转化进化的假设是因为 它在DNA修复中的作用。 为了检验这一假设，我们建议(1)继续我们的研究 转化细胞和未转化细胞的存活率，(2) 检验重组的染色体位置是随机的还是 与DNA损伤部位一致，(3)确定 枯草杆菌主要重组蛋白的表达水平 DNA损伤后的胜任和非胜任亚群 感受态细胞培养；(4)分离感受态细胞 从非功能细胞中分离细胞并测量它们的相对 在不同数量的情况下的频率和存活率 (5)自发性研究 细胞之间的转化而不是受体之间的转化 细胞和纯化的供体DNA，作为确定 自然条件下的转化机制，以及(6) 通过以下方式提高转化率的筛选实验 选择使用DNA损伤剂治疗的幸存者。

Our long term objective is to determine the role of DNA repair in the evolution of recombination. By studying the relationship of recombination to genetic repair, we hope to advance the understanding of what we think are two related problems. First, is the problem of how living systems have evolved in cope with agents with cause genetic damage and, hence, cancer. Second, is the problem of the evolutionary function of recombination. The proposed work will test in the eubacterium Bacillus subtilis the hypothesis that natural genetic transformation evolved because of its role in DNA repair. To test this hypothesis we propose (1) to continue our studies of the survivorship of transformed and untransformed cells, (2) to test whether chromosomal sites of recombination are random or coincident with respect to sites of DNA damage, (3) to determine the levels of the major B. subtilis recombination protein in competent and non-competent subpopulations following DNA damage to a competent cell culture, (4) experiments to isolate competent cells from noncompetent cells and to measure their relative frequencies and survivorship in the presence of varying amounts and kinds of damaging agents, (5) studying spontaneous transformation mediated between cells instead f between recipient cells and purified donor DNA, as a step towards determining the mechanisms of transformation under natural conditions, and (6) selection experiments to increase the rate of transformation by selecting survivors of treatment with DNA damaging agents.