The fact that there is a stretch of RNA at the 5' end of the Okazaki fragment emphasizes the fact that RNA does not need anything but itself to start replication. The leading strand only needs one RNA primer to begin replication since it can replicate continuously. Since the lagging strand replicated discontinuously, primers must be put down after Okazaki fragments. If this did not occur or if there was a mutation in these primers, the lagging strand would not carry out replication correctly or at all. E.coli has 5 DNA polymerases while eukaryotes have about 13. It makes sense that E. coli would have less DNA polymerases than eukaryotic DNA polymerases since eukaryotic organisms are more complex than a bacteria like E. coli. However, I did not know that there were at least 13 DNA polymerases in eukaryotes and I'm a little surprised. I have learned about several different DNA polymerases. They each seem to have their own specific function in the DNA replication process. It is important to have several DNA polymerases in case one has a mutation or fails. This will help prevent the entire process from failing. n nick translation, DNA polymerase I cuts/nicks random parts of the DNA to tag certain parts of the DNA. The tagged sequence can then be used as a probe or for IF staining.
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