While attending medical school, he also received training as an engineer specialised in hearing aids (audiologist) and graduated by the German Gesellenpruefung.
Having concluded his medical studies in 1975, Wittig successfully defended his thesis on "Purification and Characterisation of the Four Lysine-Specific Transfer Ribonucleic Acids from Chicken Embryos" (German: Reinigung und Charakterisierung der vier lysinspezifischen Transfer-Ribonukleinsäuren aus Hühnerembyronen) in 1976.
[1] Beginning in 1994, Wittig focused his research on the design, development, and clinical proof-of-concept of covalently closed DNA constructs for the treatment of cancer and for DNA-vaccines against infectious diseases.
[1] Two classes of DNA-molecules evolved through theoretical and experimental selection processes and became key technologies; MIDGE (minimalistic, immunogenically defined gene expression), and dSLIM for DNA-based immunomodulation.
[3] Guided by the goal of facilitating the independent transition from basic research into clinical DNA-based medicines, Wittig founded Mologen AG in 1998.
In late 2019, Wittig founded MolBio2Math, a non-profit foundation under the trusteeship of the Gentechnologiestiftung - Dr. Georg und Ingeburg Scheel Stiftung, of which he is currently the chairman[5]