Final answer:
Semi-conservative replication is a process where DNA is duplicated, resulting in new DNA molecules composed of one original and one new strand. It differs from the conservative and dispersive models which were disproven by experiments such as the Meselson-Stahl experiment. This replication method preserves genetic stability across generations.
Step-by-step explanation:
Semi-conservative Replication Explained
Semi-conservative replication is the process by which DNA is duplicated in all known cells. This term describes the mechanism that sees each of the two parental DNA strands serving as a template for a new strand, resulting in two new DNA molecules, each with one old (parental) and one new strand. This method is called semi-conservative because each of the original strands is conserved in the new double helix.
In contrast, other hypothesized models of DNA replication included the conservative model and the dispersive model. The conservative model suggested that the parental DNA molecule remained intact and an entirely new molecule was synthesized as a copy. This was proven incorrect as it did not explain the intermediate densities of DNA observed after replication in an experimental setting. The dispersive model suggested that the parental strands were broken into pieces that were then interspersed with newly synthesized DNA fragments; however, this too was discounted in favor of the semi-conservative model, confirmed by the Meselson-Stahl experiment in 1958.
The semi-conservative replication method ensures the passing on of genetic information with high fidelity, as each new DNA molecule contains one strand that serves as a perfect reference. This is crucial for the maintenance of genetic stability across generations.