 The central problem with using conspicuous polymorphisms for investigating the relative roles of the variety of different evolutionary forces is that they not an unbiased sample of genetic diversity with respect to either adaptive function or amount of genetic variation. Indeed, the definition of genetic polymorphism adopted by Ford (see above) incorporates the essence of both of these biases. For a period, it was believed that “The solution to our dilemma lies in the development of molecular genetics” (Lewontin 1974: 99). With the advent of electrophoresis, the amino acid sequence of a random sample of proteins from almost any organism could be studied and, for the first time, the level of genetic diversity, in the form of amino acid substitutions, across the genome could be quantified.