5.4 R EPLICATION

. R EPLICATION While proposing the double helical structure for DNA, Watson and Crick had immediately proposed a scheme for replication of DNA. To quote their original statement that is as follows: ‘‘It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material’’ (Watson and Crick, ). The scheme suggested that the two strands would separate and act as a template for the synthesis of new complementary strands. After the completion of replication, each DNA molecule would have one parental and one newly synthesised strand. This scheme was termed as semiconservative DNA replication (Figure . ). . . The Experimental Proof It is now proven that DNA replicates semiconservatively. It was shown first in Escherichia coli and subsequently in higher organisms, such as plants Figure . Watson-Crick model for semiconservative DNA replication