"Theory of Ancestral Contributions in Heredity," handwritten manuscript by Karl Pearson, published in Proceedings of the Royal Society (vol. 81:547) (1)

1971. [handwritten] [underscore]The Theory of Ancestral Contributions in Heredity[end underscore] Under the above title a paper has recently appeared by Mr. A. D. Darlishire in the R.S. Proc. Vol. 81, B, p.[illegible] giving further experimental evidence with regard to the inheritance of certain characters in peas. The paper is an interesting one, but the method adopted is not, I venture to think, capable of answering the problem which the author set himself. It has been supposed by some Mendelians that the theory of inheritance summed up in the "Ancestral Law of Heredity" was in some way invalidated by investigations such as Mr. Darlishire's and that opinion consciously or unconsciously seems to be expressed in the paper just referred to. The ancestral law of heredity is summed up in the following statements: (i) In a population breeding without assortative mating, the regression time for offspring on any ancestor is linear. (ii) The correlations between offspring & the successive grades of ancestry form a geometrical progression diminishing as we ascend to distant grades, and (iii) The general relation of an individual to his ancestry can be [illegible] by the multiple correlation formula. [end]