The mechanism and physiology of sex determination / by Richard Goldschmidt ; translated by William J. Dakin.

  • Goldschmidt, Richard, 1878-1958.
Date:
1923
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The mechanism and physiology of sex determination / by Richard Goldschmidt ; translated by William J. Dakin. Source: Wellcome Collection.

    263/292 (page 235)
    SEX DETERMINATION IN MAN 235 spermatogenesis with reference to the sex chromosomes, found only twenty-two chromosomes, and beheved that at the matura¬ tion divisions two sorts of spermatids were formed, some with ten and some with twelve chromosomes. This was contradicted by Gutherz and also by all other observers. Montgomery again found twenty-four as the normal number of which two formed an XY pair. In the maturation divisions these were in many cases separated in the manner required by the digamet- ism scheme and half the sperms contained i г + X, the other half 11 + Y. But in many cases the distribution was different, so that finally no fewer than four to six kinds of spermatozoa were produced. From this view again Winiwarter completely diverged. He found forty-seven chromosomes to be the normal number in the spermatogonia, and in the maturation divisions two kinds of sperms were produced, those with twenty-three and those with twenty-four chromosomes. He also found forty-eight chromosomes in the ovary of a foetus, so that we have typical male heterogametism with forty-seven chromosomes as the male number and forty-eight as character¬ istic of the female. An attempt has been made to clear away the extraordinary differences between the discoveries of Guyer and Montgomery on the one side, and Winiwarter on the other, on the ground that the first-named authors investigated negro materia], the latter European. Cases are known in both the animal and plant worlds v^here closely related races differ in the chromosome numbers in the relations n:2n (for example, A scar is ^ A rtemia^. But at the same time it was forgotten that Hansemann, Flemming, and Duesberg had investigated Europeans and also found twenty-four chromosomes as the normal number. The investigation of Wieman^ has been carried out on negro material and also on white, and he finds the normal number always twenty-four. Among these there is an XY pair that as usual is distinguished by its special conduct during the spermatogenesis. In the second spermatocyte division it is separated with one half of the autosomes, and the result is female-determining sperms with ii + X and male-determining with 11 + Y chromosomes. 1 Wieman, H. L., The Chromosomes of Human Spermatocytes. Amer. Journ. Anat., 21, 1917-