. Readings in evolution, genetics, and eugenics. Evolution; Heredity; Eugenics. SEX DETERMINATION 451 the male gametes have one X chromosome and the other half have no X, but sometimes Y and sometimes simply one chromosome less than the first type of male gametes. We can then speak of the two. Fig. 94.—An armadillo egg about six weeks after fertilization, showing the quadruplet foetuses are derived from the single egg and all destined to be of the same sex. {From Newman.) sexes produced by union of male and female gametes simply in terms of the X chromosomes, females being characterized by XX


. Readings in evolution, genetics, and eugenics. Evolution; Heredity; Eugenics. SEX DETERMINATION 451 the male gametes have one X chromosome and the other half have no X, but sometimes Y and sometimes simply one chromosome less than the first type of male gametes. We can then speak of the two. Fig. 94.—An armadillo egg about six weeks after fertilization, showing the quadruplet foetuses are derived from the single egg and all destined to be of the same sex. {From Newman.) sexes produced by union of male and female gametes simply in terms of the X chromosomes, females being characterized by XX (duplex) and males by X (simplex). SEX DETERMINATION IN PARTHENOGENETIC SPECIES Although it was at first thought that the facts of parthenogenesis (development of eggs without fertilization) was opposed to the chromosomal mechanism of sex determination, further study of this. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Newman, Horatio Hackett, b. 1875. Chicago : University of Chicago Press


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