In 2001, Rogers's gave a proof of identifiability for the popular general time reversal Markov model with Gamma distributed rates mixed with invariable sites for DNA evolution along a phylogeny. Recently, Allman, Ane, and Rhodes have pointed out an error in Rogers's proof and provided a proof using the tools of algebraic statistics to show that the model without the invariable sites is identifiable. We will discuss Rogers's approach and provide the proof of the missing link for the model with invariable sites for generic parameters. We reduce the set of exceptional cases to only the Jukes-Cantor model. We will discuss what is known about that model to date