Concept explainers
As shown in Figure 11.5, five DnaA boxes are found within the origin of replication in E. coli. Take a look at these five sequences carefully.
A. Are the sequences of the five DnaA boxes very similar to each other? (Hint: Remember that DNA is double-stranded; think about these sequences in the forward and reverse directions.)
B. What is the most common sequence for a DnaA box? In other words, what is the most common base in the first position, second position, and so on until the ninth position? The most common sequence is called the consensus sequence.
C. The E. coli chromosome is about 4.6 million bp long. Based on random chance, is it likely that the consensus sequence for a DnaA box occurs elsewhere in the E. coli chromosome? If so, why aren’t there multiple origins of replication in E. coli?
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Genetics: Analysis and Principles
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- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning