Daryl and T-Dog were invented for the TV series, they have no equivalent in the comics. The CDC wasn't included in the comic because Kirkman didn't know they were located in Atlanta.
I get that but Tyreese and T-dog could easily be the same character.
Did we ever learn T-dog's real name? I don't remember.
It's also weird seeing Tyreese playing duel roles and doing things with Rick that Shane and Daryl did/does in the show.
Even though I liked T-dog I think Tyreese is a much more interesting Character.