On the Genetic Structure of Inherited Constitution for Disease Resistance

Abstract

The genetic basis for the resistance to 2 or more diseases has been interpreted in 2 rather distinct ways: (1) The resistance is held to be of the single unit type which enables the animal to resist a number of diseases or poisons; (2) a resistant constitution is held to be a composite character made up of numerous genetic factors, some making for resistance to one disease and some to another, the fortuitous combination of these factors leading to resistance to both. The paper presents a study of resistance of mice to mouse typhoid and pseudorabies. This evidence indicates that the genetic constitution of the host is a primary variable in the disease syndrome. The genetic organization of the pathogen has like importance. Evidently the genetic constitutions of both must properly fit together for the pathogen to invade the host and produce the characteristic clinical picture of the given disease. The comparison of the susceptibility of a population to 2 or more diseases shows that in the majority of critical cases the genetic constitution of the host is a composite of numerous independent factors, some favoring resistance to one environmental agent and some to another, the fortuitous combination of these separate factors making the organism resistant to many or few such agents.