BACTERIOPHAGE T4 RI MUTATIONS

诱变剂增加了人类可遗传生育的负担 缺陷和癌症，可能还有心脏病。 噬菌体T4已被广泛用作模型系统 分析诱变机制。其中最 常见的T4突变检测通过以下方式识别r(快速裂解)突变体 他们巨大的边缘锐利的斑块。尽管RII突变体 那些最常接受进一步分析的，最具诱变剂的 产生更多的RI和RII突变体。由于人们对ri知之甚少 突变体，我们研究了它们的一般性质。 产生特征ri表型的突变可归结为 两个位置，其中一个是经典描述的大约1：30的位置 标准地图和另一个轨迹在8：30左右。点突变 在1：30位点以低频率重组时， 暗示是一个小基因；几个基因被未连锁的但 到目前为止还没有被映射的抑制子突变。“8：30”的轨迹正在被 更紧密地映射。

Mutagens contribute to the human burden of heritable birth defects and cancer and probably to heart disease as well. Bacteriophage T4 has been widely employed as a model system to analyze mechanisms of mutagenesis. One of the most common T4 mutation assays recognizes r (rapid lysis) mutants by their large, sharply edged plaques. Although the rII mutants are those most often subjected to further analysis, most mutagens produce more rI and rII mutants. Since little is known about rI mutants, we have investigated their general properties. Mutations that produce the characteristic rI phenotype fall into two loci, one the classically described locus at about 1:30 on the standard map and another a locus at about 8:30. Point mutations at the 1:30 locus recombine inter se at low frequencies, suggesting a small gene; several are suppressed by unlinked but as yet unmapped suppressor mutations. The "8:30" locus is being more closely mapped.