MULLER ON DEVELOPMENT

Contrary to Morgan, who viewed the genes from the cells' point of view as components of the cell's metabolic system, H. J. Muller conceived of the genes, on theoretical grounds, as the ''atoms of life'', the ba sic units that control and direct the development of the cells by dete rmining their synthetic processes. This allowed Muller to formulate de velopmental problems in terms that the genetic machinery could answer, rather than to superimpose the developmental and physiological questi on-posing on the genetic system. Following E. B. Wilson, he considered the Mendelian analysis as a reductionist methodology for the study sp ecific, differential factors of ontogenetic reaction in a complex orga nic system. He insisted on the need to study the pleiotropic phenotypi c effects of mutants of many specific genes, in order to deduce from t hese information on the normal sequence of development. He had to admi t, however, that with the methods available at the time this was only rarely a practical task. Of more immediate appeal to him were studies on the principles of the involvement of genes in the determination of characters, as revealed by the mutagenic manipulations of the genes.