DNA is known to copy itself in a semi-conservative manner. The results from Meselson and Stahl’s experiments provided very strong support for this theory. They worked with $E.\ coli$, which has a generation time of 50 minutes. The stages in their experiment are listed below, but the order is incorrect. P All bacteria contain $^{15}\text{N}$ DNA. Q All bacteria contain hybrid DNA ($^{15}\text{N}$ DNA and $^{14}\text{N}$ DNA). R Bacteria contain either all $^{14}\text{N}$ DNA or hybrid DNA. S Bacteria were grown in a $^{15}\text{N}$ medium for many generations. T Bacteria were moved to a $^{14}\text{N}$ medium and sampled every 50 minutes. Which sequence of letters shows the correct order of the steps in the experiment?
- AP → Q → R → S → T
- BP → S → T → R → Q
- CS → P → T → Q → R
- DS → R → Q → P → T