XXXIV.—The Significance of the Correlation Coefficient when applied to Mendelian Distributions

Abstract

1. At the present moment there is much discussion regarding the means by which properties are hereditarily transmitted from a parent organism to its offspring, and of the extent to which the Mendelian theory is capable of accounting for the facts. In this note it is not proposed to discuss the general question but to investigate the conditions under which the theory of correlation may be applied to Mendelian groupings. Two important papers on this subject have already been published: one by Professor Pearson, entitled “A Generalized Theory of Mendelian Inheritance”; the other, which is largely a criticism of this, by Professor Udny Yule. In Professor Pearson's paper the results produced when two organisms with any number of pairs of different zygotes mate indiscriminately are fully considered. He finds that such a population once established is stable, and he then deduces the parental and fraternal correlation coefficients.