Rates Of Spontaneous Mutation

1.核糖病毒是人类病原体中最大的一类，其突变率很难测量。特别是，核糖病毒是否具有共同的基因组突变率的问题一直难以解决。经过多次努力，我们建立了一个模型系统，使用噬菌体Q上生长的细菌大肠杆菌。正如从核糖体病毒所预期的那样，突变率非常高，每个基因组复制约0.04。不同类型的突变的比例与大多数其他生物体中所见的不同，其中过渡到颠换碱基取代的比例特别高，并且很少有插入缺失偏向于单碱基插入。我们也能够测试的假设，即核糖病毒复制的冲压机过程，而不是指数复制，冲压机假说的支持。 2.近年来，一些研究小组已经使用全基因组DNA测序来表征自发突变。 这些方法有潜在的缺陷，结果有时似乎与以前使用更完整方法的报告相矛盾。 描述了这种矛盾的一个例子，并将其归因于在培养过程中未实现的突变损失。

1. Mutation rates are difficult to measure in riboviruses, the largest class of human pathogens. In particular, the question of whether riboviruses share a common genomic mutation rate has resisted resolution. After many efforts, we established a model system using the phage Q growing on the bacterium Escherichia coli. As expected from a ribovirus, mutation rates are very high, about 0.04 per genome replication. The ratios of different kinds of mutations differ from those seen in most other organisms, with a particularly high ratio of transition to transversion base substitutions and with very few indels with a bias towards single-base insertions. We were also able to test the hypothesis that riboviruses replication by a stamping-machine process rather than by exponential replication, with the stamping-machine hypothesis supported. 2. In recent years, several groups have characterized spontaneous mutations using whole-genome DNA sequencing. The methods have potential pitfalls and the results sometimes appear to contradict previous reports using more fully established methods. An example of such a contradiction was described and attributed to the unrealized loss of mutations during the passage of the cultures.