Question

Why is DNA replication in living cells so much more complicated than DNA amplification in the lab? Could organisms evolve a system as simple as PCR?

Answer 1

Answer :)

Living cells have to use DNA many times throughout their life for many purposes. Under the laboratory, we just focus a particular part of DNA, which may just 0.1% of its total length, for the replication. But in living cells the whole length of DNA should be replicated within a short period, otherwise, daughter cells will not survive. That is why the living system has many different components than the PCR, just in case – Living cells have helicase enzyme for the unwinding of DNA, ligase enzyme utilizing for ligation of strands, many replication origins to complete the DNA replication, etc.

Of course, cells can evolve themselves and become a natural PCR, under natural pressure. For that, the cells have to kill many parts of their replication system.