What is 'semi- conservative' DNA replication ? How was it experimentally proved and by whom ?

Explanation

### Step-by-Step Solution

1. **Definition of Semi-Conservative DNA Replication**:
Semi-conservative DNA replication is a process in which each strand of the original DNA molecule serves as a template for the synthesis of a new complementary strand. As a result, each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.

2. **Experimental Proof**:
The concept of semi-conservative DNA replication was experimentally proven by scientists Matthew Meselson and Franklin Stahl in 1958 (not 1857 as mentioned in the transcript). They designed an experiment using the bacterium *Escherichia coli* (E. coli) to demonstrate this process.

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