What is semiconservative DNA replication?

Semiconservative replication means that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand. This was demonstrated by Meselson and Stahl in 1958 using density gradient centrifugation with heavy nitrogen isotopes. During replication, the double helix unwinds at origins of replication, and each strand serves as a template for synthesizing a complementary strand. This mechanism ensures accurate transmission of genetic information and was predicted by Watson and Crick based on DNA structure.