Gierer & Schramm's Second Experiment with TMV

    Look at the third leaf:

    You see the two small spots. Were these caused by a few contaminating original undissociated virions? Just to assure themselves of the protein-free nature of their TMV-RNA preparation they added some protease, which chews up all proteins, then reswabbed this purified TMV-RNA onto leaves getting:

    You see the spots continue to be made - but in very low efficiency. It is as if a few of the RNA molecules were able to get into the leaf cells - perhaps through damage caused by the swabbing. This greatly added weight to the notion that RNA is the genetic material of TMV!

    Rosalin Franklin, in a huff, left her association with Watson, Crick and Wilkins, and soon revealed how the TMV virion was assembled. Alas, she soon died of pancreatic cancer presumably from all the radiation used during her studies of X-ray diffraction patterns leading to the elucidation of the structure of DNA. Only living persons can be awarded the Nobel Prize, thus she is not included in the list of names for the structure of DNA.

    Later it was shown that there are many DNA viruses and RNA viruses, but that no virus contained BOTH DNA and RNA.