Gilbert returned to Harvard in 1956 and was appointed assistant professor of physics in 1959. In 1964 he was promoted to associate professor of biophysics and promoted again in 1968 to professor of biochemistry. and
Myriad Genetics with Dr. Mark Skolnick and
Kevin Kimberlin where he was the first chairman on their respective boards of directors. Gilbert left his position at Harvard to run Biogen as CEO, but was later asked to resign by the company's board of directors. He is a member of the Board of Scientific Governors at
The Scripps Research Institute. Gilbert has served as the chairman of the
Harvard Society of Fellows. In 1996, Gilbert and
Stuart B. Levy founded Paratek Pharmaceuticals. Gilbert served as chairman until 2014. Gilbert was an early proponent of sequencing the
human genome. At a March 1986 meeting in
Santa Fe New Mexico he proclaimed "The total human sequence is the grail of human genetics". In 1987, he proposed starting a company called Genome Corporation to sequence the genome and sell access to the information. Gilbert returned to Harvard in 1985. Gilbert was an outspoken critic of
David Baltimore in the handling of the scientific fraud accusations against
Thereza Imanishi-Kari. Gilbert also joined the early
controversy over the cause of AIDS. In 1962, Gilbert's physics PhD student
Gerald Guralnik extended Gilbert's work on massless particles; Guralnik's work is widely recognized as an important thread in the discovery of the
Higgs Boson. With his PhD student
Benno Müller-Hill, Gilbert was the first to purify the
lac repressor, just beating out
Mark Ptashne for purifying the first gene regulatory protein. Together with
Allan Maxam, Gilbert developed a new
DNA sequencing method,
Maxam–Gilbert sequencing, lost out to
Genentech's approach which used genes built up from the nucleotides rather than from natural sources. Gilbert's effort was hampered by a temporary moratorium on recombinant DNA work in
Cambridge, Massachusetts, forcing his group to move their work to an English biological weapons site. Gilbert first proposed the terms
introns (intragenic regions) and
exons (expressed regions) in reference to recently discovered phenomenon of splicing and suggested explanation for the evolution of introns in a seminal 1978 "News and Views" correspondence to
Nature titled "why genes in pieces?". In 1986, Gilbert proposed the
RNA world hypothesis for the
origin of life, based on a concept first proposed by
Carl Woese in 1967. ==Awards and honors==