The major contribution of the Thomas Hunt Morgan School of Drosophila genetics was to establish, beyond a reasonable doubt, that the Mendelian factors are parts of chromosomes. That hypothesis was first stated, with great clarity, by Walter S. Sutton in 1903. The supporting data were few and most biologists, including Morgan, found the argument insufficient. In 1910 Morgan reversed his position when he began his analysis of the inheritance of sex-linked mutants in Drosophila.

Author notes

1From the symposium on The place of thomas hunt morgan in american biologypresented at the annual meeting of american society of zoologists,27–30 december 1982 at Louisville, Kentucky.