Comment by vaylian

This is really smart. By making it impossible for the cells to generate Thymidine, they can not create more DNA which is needed to produce the genome of two (possibly malignant) daughter cells. Why Thymidine? Because there is a key difference between DNA and RNA: DNA has Thymine while RNA has Uracil. Both DNA and RNA share the other 3 bases: Adenine, Cytosine and Guanine. The cell only needs additional DNA if it goes into cell division, but it needs RNA all the time for many cellular processes. Singling out Thymidine is a really cool idea!