Daniel St Johnston is a biologist best known for his key studies on Drosophila fruit flies, which have increased our understanding of how the body axes are correctly established during development. Through his work, Daniel provided the most detailed description ever made of how axis formation arises.

He also pioneered the study of the mechanisms by which messenger RNAs — single strands of nucleic acid used in the construction of proteins — are localised within cells. More recently, his work has focused on cell polarity, evolutionary conserved methods that establish differences between the two ends of a cell. Polarity research is of great importance since cancerous cells often lose their polarity.

Daniel is Professor of Developmental Genetics at the University of Cambridge. He performs his research at the Gurdon Institute, founded to promote research in developmental biology and cancer biology. His laboratory group continues to use Drosophila as a model organism in which to study development.