semiconservatively

Semiconservatively is an adverb describing a process conducted in a semiconservative manner, most often in reference to DNA replication. In this context, each resulting DNA duplex contains one strand derived from the original parent molecule and one newly synthesized strand. This description summarizes how genetic information is preserved while new material is added.

The term relates to the semiconservative replication model, which was proposed to explain how replication preserves parental information. The model received strong experimental support from the Meselson–Stahl experiment in 1958, which used isotopic labeling of DNA in Escherichia coli to show that daughter molecules retain one old strand and one new strand after replication. Today, DNA replication in bacteria, archaea, and eukaryotes is understood to proceed semiconservatively, with replication forks, helicases, primases, DNA polymerases, and ligases coordinating the process.

While semiconservative replication is the widely accepted paradigm, it contrasts with other historical models such as conservative and dispersive replication. The semiconservative view remains central to discussions of genome duplication, repair, and recombination, where maintaining one parental strand in each daughter molecule is a defining feature. In scholarly writing, researchers might state that the replication machinery copies the genome semiconservatively, reflecting its fundamental nature in molecular biology.

See also: Meselson–Stahl experiment; DNA replication; replication fork; DNA polymerase.