Julian Bashir

Born with serious learning disabilities, parents illegally got him genetically altered;
2348: Mental abilities were increased & physiology was enhanced
2368: Graduated as salutatorian, missing one question on the final
2369: Chose an assignment aboard Starbase Deep Space 9
2372: Discovered an in-vitro vaccine for the blight
2373: Held captive by the Dominion, replaced by a Changeling, rescued months later
2373: Exposed as an Augment, allowed to stay in Starfleet
2374: Approached by Luther Sloan, to join Section 31, refused the offer
2375: Got the cure for the morphogenic virus which had infected Odo & the Changelings;
Remained on Deep Space 9 following the war