Agronomy and Horticulture Department


Date of this Version



Science, New Series, Vol. 34, No. 877 (Oct. 20, 1911), pp. 512-513


Copyright 1911 R. A. Emerson


To the editor of science: The suggestion offered by Morgan, in SCIENCE of September 22, to account for the coupling and repulsion of factors for various characters in inheritance in such forms as Abraxas, Drosophila, fowls, sweet peas, etc., incites this note.

Briefly Morgan's hypothesis is (1) that the materials representing factors that couple are "near together in a linear series" in the chromosomes; (2) that, when pairs of parental chromosomes conjugate, "like regions stand opposed "; (3) that "homologous chromosomes twist around each other," but that the separation of chromosomes is in a single "plane"; (4) that, thereby the "original materials will, for short distances be more likely to fall on the same side of the split," while more remote regions will be as likely to fall on one side as on the other; (5) that, in consequence, whether characters are coupled in inheritance or are independently inherited depends upon the "linear distance apart of the chromosomal materials that represent factors."