Semi-conservative replication of DNA was first demonstrated in
(1) Drosophila melanogaster
(2) Escherichia coli
(3) Streptococcus pneumoniae
(4) Salmonella typhimurium
(2) Semi-conservative replication of DNA was first demonstrated in E. coli. According to the semi-conservative mode proposed by Watson and Crick, each strand of the two double helices formed would have one old and one new strand. The semi-conservative nature of DNA replication was proved by the experiment of Meselson and Stahl (1958).