What type of replication occurs in DNA?

DNA replication is described as semi-conservative because, during the process, each of the two resulting DNA molecules contains one original (parental) strand and one newly synthesized strand. This method of replication was confirmed through experiments, such as those conducted by Meselson and Stahl, which demonstrated that when bacteria were grown in heavy nitrogen and then switched to normal nitrogen, the DNA showed a hybrid density after one round of replication, indicating that each new double helix consisted of one template strand from the parent and one new strand.

In semi-conservative replication, the parental DNA serves as a template for the creation of new complementary strands, ensuring fidelity and continuity of genetic information across generations. This mechanism is crucial because it minimizes the risk of errors that could occur if either a conservative (where both strands serve as templates, but the original double helix remains intact) or dispersive (where the parental DNA is broken into segments and mixed with new DNA) replication method were used. Each of these alternatives would create uncertainties and potential mismatches in the genetic sequences of the daughter strands.