While doing research on deep-sea vents, you discover a very simple new life form. After some initial analysis, you find that this life form contains small fragments of DNA, small complementary RNA fragments, and proteins. Fortuitously, you collected two strains, one that is purple and one that is yellow.
-You wish to discover which of those three molecules could be the genetic material. The classic experiment of which of the following scientists would be the MOST appropriate to mimic?