. Readings in evolution, genetics, and eugenics. Evolution; Heredity; Eugenics. Fig. 60.—Some divergent types (mutations) of beetles produced by subject- ing the germ cells to external influences. A, normal decemlineata; B, the form pallida; C, torluosa; D, defectopunctata. {From Tower.) new characters (Fig. 61) which bred true to t5^e for four or more generations. Whether or not the changes persisted longer we do not know, since MacDougal has not published any further details. Gager discovered that the action of radium rays on the pollen grains of various plants had a profound effect upon the
. Readings in evolution, genetics, and eugenics. Evolution; Heredity; Eugenics. Fig. 60.—Some divergent types (mutations) of beetles produced by subject- ing the germ cells to external influences. A, normal decemlineata; B, the form pallida; C, torluosa; D, defectopunctata. {From Tower.) new characters (Fig. 61) which bred true to t5^e for four or more generations. Whether or not the changes persisted longer we do not know, since MacDougal has not published any further details. Gager discovered that the action of radium rays on the pollen grains of various plants had a profound effect upon the chromatin. Some of the latter was apparently lost during mitotic cell division. The same writer exposed the ovules of plants to radium rays and pro- duced marked changes in the germ cells so that they grew into various. 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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