He invented some of the mathematical methods used to map human genes.[1] In 1955, he invented the "gene counting" method of inferring gene frequencies from the frequencies of genotypes in populations.[2] This was an early example of the EM Algorithm, over 20 years before its introduction by Dempster, Laird and Rubin. He gave a more general discussion of the gene-counting method and its statistical properties in 1957.[3]