PCR ANALYSIS OF STARVATION INDUCED DNA REARRANGEMENTS

现在被广泛接受的是，压力条件导致通过选择测量的突变频率的增加。“定向突变”问题现在提出的问题是由特定的压力制度引起的变化的特异性。为了回答这个问题，有必要描述所有的DNA变化，而不管它们是否在选择条件下促进生长。这现在可以通过PCR技术来实现。PCR可以检测基因组的特定区域，并检测新的DNA结构，即使它们不能通过生长来选择。初步结果表明，由Mu噬菌体转座因子介导的一类特定DNA重排在正常生长条件下无法测量，但在选择性条件下相对较高的频率下很容易检测到。现在使用聚合酶链反应可以检测这种基因重排发生的频率和时间，无论是否使用测量突变率通常需要的选择性技术。

It is now widely accepted that stress conditions lead to an increase in the frequencies of mutation measured by selection. The question now raised by the "Directed mutation" issue is the specificity of the changes induced by particular stress regimes. To answer this question, it is necessary to characterize all DNA changes regardless of whether they facilitate growth under selective conditions. This can now be done by PCR technology. PCR makes it possible to examine specific regions of the genome following stress and detect novel DNA structures, even if they can not be selected by growth. Initial results demonstrated that a specific class of DNA rearrangement mediated by the Mu phage transposable element did not measurably occur under normal growth conditions but were easily detectable at relatively high frequencies under selective conditions. Use of PCR will now allow detection of the frequency and time of occurance of such genetic rearrangements with and without the selective techniques that are usually required for measuring mutation rates.