NEETZoologyMolecular Basis of Inheritance
How was the heavy DNA molecule distinguished from the normal DNA in the experiments performed by Meselson and Stahl?
Options
- ABy using radioactive isotopes
- BBy separating it based on its size
- CBy separating it based on its density
- DBy separating it based on its color
Correct answer
C. By separating it based on its density
Step-by-step solution
The result was that 15N was incorporated into newly synthesized DNA (as well as other nitrogen containing compounds). This heavy DNA molecule could be distinguished from the normal DNA by centrifugation in a cesium chloride (CsCl) density gradient (Please note that 15N is not a radioactive isotope, and it can be separated from 14N only based on densities). (ii) Then they transferred the cells into a medium with normal 14NH4Cl and took samples at various definite time intervals as the cells multiplied, and extracted