Paracrinkle Virus and Inheritance

Abstract

IN his recent interesting article¹, Dr. Darlington speculates on the origin of viruses and in particular on that of paracrinkle virus in the potato variety King Edward. He states with reference to paracrinkle that "what is a stable and presumably useful cell protein with one plant genotype acts as a destructive agent with another"; also that "any virus that can be transmitted only by grafting must therefore have arisen from grafting; that is to say, from the invasion of one plant by the proteins of another". We gather from this that Dr. Darlington considers that a protein constituent of King Edward becomes a virus on transference by grafting to another potato variety. While this is a tempting speculation, whatever evidence there is does not support it, and we should like to point out the following facts.