The Gene Interaction Component of the Genetic Load

I T has usually been considered that the principal components of the genetic load are the mutation and segregation loads, plus some presumably smaller components such as the load due to selection for an intermediate optimum of a quantitative character I would propose that the interaction of deleterious genes constitutes another distinct component, because of the unique distinguishing characteristics of this source of variation in fitness. The magnitude of the interaction component relative to other components is as yet unknown. It is the purpose of this article to propose further that the interaction component may be a major part of the genetic load, and to explore the implications of such a hypothesis.