86 



AN INTRODUCTION TO MODERN GENETICS 



Fig, 37. Gynandromorphs. — On the left above is a diagram of the first cleavage 

 of a female egg, showing one of the X chromosomes being eliminated by lagging 

 on the equator of the spindle. Belov/ is the resulting gynandromorph, whose 

 left side is female (XX) and shows the dominant character Notch, while the 

 right side is male (XO), having lost the Notch X-chromosome and showing the 

 recessives scute (no bristles on scutellum), broad (wing), echinus (rough eye), 

 ruby (eye colour), and tan (body colour) from its remaining X. 



(From Morgan, Bridges, and Sturtevant.) 



On the right is the head of a fly from which an X-chromosome has been 

 eliminated from a late somatic mitosis. The mosaic spot shows the eye colour 

 cosjn and singed bristles, for which the fly as a whole was heterozygous. 



(From Bridges.) 



