Returning from military service, he took a fellowship at
Johns Hopkins University. He returned to Liverpool, where he rose to the rank of Professor of Haematology. His research concentrated on the genetics of the haemoglobinopathies and, in particular, a group of inherited haematological disorders known as the
thalassemias that are associated with abnormalities in the production of globin, the protein component of haemoglobin. Weatherall was one of the world's experts on the clinical and molecular basis of the thalassemias and the application for their control and prevention in developing countries. In 1974, Weatherall moved to Oxford, as he was appointed
Nuffield Professor of Clinical Medicine at the
University of Oxford. He worked with the biochemist
John Clegg until his retirement in 2000. They were able to separate the α and β chains of haemoglobin and to demonstrate that the relative lack of production of these proteins resulted in α and β thalassaemia. In 2002, Weatherall wrote a major report on the application of
genomics for global health for the
World Health Organization. During this year, he also became
Chancellor of
Keele University.. Weatherall was a Distinguished Supporter of
Humanists UK. In 2009, a working group report under Weatherall's Chairmanship concluded that there was a strong scientific case to maintain biomedical research activities using non-human primates in carefully selected areas. ==Awards and honours==