Hologynic Heredity.

Sex-linked characters in man are well known; they are all pathological characters, so far as known; they are transmitted according to the same laws as the sex-linked characters in the little fruit-fly (Drosophila) and explained in the same manner by means of the sex chromosome. I propose the name “diagynic heredity” for this kind of heredity, as the sex-linked character is transmitted from male to male, not directly, but through the unaffected females (e. g., hemophilia, daltonism). In the currant moth ( A braxas grosszclariata) the character “lacticolor” is transmitted from female to female, not directly, but through the “unaffected” males. This “dia-andric heredity” is not known in man. A third kind of sex-linked heredity is possible. We know two pedigrees of this kind (daltonism, hemophilia), and two new pedigrees are referred to in this paper (hemophilia, cataract). No one has considered this special kind of heredity or noticed its theoretical and practical importance. For the pedigree of daltonism (CUNIER), see PLATE 1913, p. 379. Daltonism is usually diagynic; but in this pedigree 12 females are affected in 5 generations. The authors have not emphasized the circumstance that all the females are affected. The males are all unaffected. The transmission is direct from the affected female to her daughters. In another pedigree of hemophilia (GRANDIDIER, see PLATE 1913, p. 379), an affected mother has three affected daughters and no other children; her parents, according to the reference, are unaffected. I propose for this type of heredity the name of “hologynic heredity.” “Holo-andric heredity” has not been recognized, heretofore, but in the Jozcrrtd of Heredity for November 1921 RICHARD SCHOFIELD has published a pedigree of webbed toes with 14 affected males in 4 generations (all the males) and not one female. SCHOFIELD does not recognize in this pedigree a new form of heredity and thinks that this hereditary trait is inherited as a secondary sex character. But why are all the males affected?