File:The elements of genetics (1950) (21262823541).jpg

Title: The elements of genetics
Identifier: elementsofgeneti00darl (find matches)
Year: 1950 (1950s)
Authors: Darlington, C. D. (Cyril Dean), 1903-; Mather, Kenneth
Subjects: Genetics
Publisher: New York : Macmillan
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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BASES OF CHANGH in chimaeras which themselves have arisen from a single original mutation (cf. Fig. 22). In animals the effects of somatic mutation are slightly different. Development and life being limited, the mixture is not a permanent one. Development being less simple the mixture is also less regular. As a result, the changed cells give flakes and sectors instead of layers
Text Appearing After Image:
Fig. 23.—Gynandromorph of Drosophila melanogastcr. The left side is XX and female. One X carrying the dominant gene Notch, whose effect appears in the left wing, has been lost on the right side which is therefore male and shows the effects of the recessive genes of the other X, viz. ruby (eye colour), scute (bristle reduction), broad (wing), and forked (bristle gnarling). The whole fly is slightly warped owing to the male side being shorter than the female (from Morgan, Bridges and Sturtevant, 1925). and the product is known as a mosaic instead of a chimaera. There is, however, one regular type of mixture of particular interest and this is the gynandromorph. Such monsters, male in one part and female in the rest, arise from a genetic difference between a pair of nuclei produced at an early mitosis in the embryo. They give various mixtures according to the stages and relative positions of the mitoses, but perhaps the commonest is the half-sidcr of the type shown in Fig. 23. They come about in a variety of ways as can be proved by genetic as well as by cytological evidence (Fig. 24). 1J2

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