90 



HEREDITY AND SEX 



GR9 GR$ GWS YR$ YW $ 



4 1111 



These results are illustrated by means of Fig. 48, 

 in which the yellow color of the fly is indicated by 

 stippHng the body and wings, and the red eyes by 

 black. The X chromosome is also marked and colored 



XX 



X( 



I 



IX XXX' 



Fig. 48. — Inheritance of yellow-white {$) and gray-red ( 9 ) of Dro- 

 sophila. In Fi both sexes are gray-red. In F2 are produced 4 GR 9 — 

 I GR $ — I GW $ — I YR $ — I YW $ . 



