2 - The Differential Concept of the Gene: Past and Present

Summary

ABSTRACT

The differential concept of the gene was created by geneticists at the beginning of the twentieth century to fill the need for a workable research method given the newly established formal theory that claimed many-to-many relationships between genes and traits. This concept can be reconciled with both one-to-one and many-to-many relationships between genes and traits because it deals with a different ontological level: the relationships between changes in genes and changes in traits, rather than the nature of the entities themselves. This flexible nature may also allow the term gene to survive its replacement by the term genome. The differential concept of the gene, except for its predicate, is not specific to genetics. The concept is fundamental, though to some degree intuitive, hence exhibiting power and weakness. Also, it is used continuously in studies of connections between the genotypic and phenotypic levels. In contrast to classical transmission genetics, where the interest in the relations between mutations and alternative appearances of traits is derived mainly from the need for a research method, the present interest is twofold: a research method and a research subject. The present use of the differential concept of the gene is characterized by its refinement: Different alternative states of a gene are to be related to different alternative appearances of a trait. This requires resolution capability at both the genotypic and phenotypic levels and is guided by the reductionist assumption that at least some mutations make a difference in the phenotype.