Professor Bryan Campbell Clarke (24 June 1932 – 27 February 2014) was a British geneticist, latterly professor emeritus of genetics at the University of Nottingham. Clarke is particularly noted for his work on apostatic selection (which is a term he coined in 1962) and other forms of frequency-dependent selection, and work on polymorphism in snails, much of it done during the 1960s. Later, he studied molecular evolution. He made the case for natural selection as an important factor in the maintenance of molecular variation, and in driving evolutionary changes in molecules through time. In doing so, he questioned the over-riding importance of random genetic drift advocated by King, Jukes, and Kimura. 

With Dr. JJ Murray Jnr (University of Virginia), he carried out an extensive series of studies on speciation in land snails of the genus Partula inhabiting the volcanic islands of the Eastern Pacific. These studies illuminated the genetic changes that take place during the origin of species.He was awarded the Darwin Medal of the Royal Society in 2010 for his original and influential contributions to our understanding of the genetic basis of evolution.