The Mechanism of Heredity

Abstract

The theory of pangenesis receives its most complete exposition in the book which Darwin wrote to provide the full evidence needed to sustain the argument of The Origin of Species. This book — Animals and Plants under Domestication — was first published in 1868, and a second edition appeared in 1888. In it we find the following passage:

How again, can we explain the inherited effects of the use, or disuse of particular organs? The domesticated duck flies less and walks more than the wild duck, and its limb bones have become diminished and increased in a corresponding manner in comparison with those of the wild duck. A horse is trained to certain paces, and the colt inherits similar consensual movements. The domesticated rabbit becomes tame from too close confinement, the dog, intelligent from associating with man; the retriever is taught to fetch and carry; and these mental endowments and bodily powers are all inherited. Nothing in the whole circuit of physiology is more wonderful. How can the use or disuse of a particular limb or of the brain affect a small aggregate of reproductive cells, seated in a distant part of the body, in such a manner that the being developed from these cells inherits the characters of either one or both parents? Even an imperfect answer to this question would be satisfactory (1).