With this, he distinguished several electrophoretically different polymorphic serum protein (haptoglobins, transferrins, and the like). In 1957 and for several years after, in collaboration with Anthony Allison who was then in the Department of Biochemistry in Oxford, we studied these variants in Basque, other European, Nigerian, and Alaskan populations and found striking variations in gene frequencies.

Using these and similar techniques in the following years, I studies inherited variants in other populations and regions. We identified several "new" polymorphisms in animals.

From these studies and those of other investigators, the richness and variety of biochemical and antigenic variation in serum became strikingly apparent.