TWO NEW EYE COLORS IN DROSOPHILA MELANOGASTER. 2OI 



second, with sooty of the third, and with eyeless of the fourth. 

 The results of these crosses demonstrated that scarlet is a member 

 of the third group of linked genes. When scarlet was crossed to 

 blood, vestigial, or eyeless, all possible combinations were formed 

 in p2, showing that independent assortment occurs between these 

 genes and scarlet. However, when scarlet was crossed to sooty, 

 no scarlet sooty flies were obtained in p2. The crosses gave the 

 following results : 



1. Scarlet cf X Blood 9 (first chromosome character). 



Fi Wild-type 9 , blood o 71 

 Wild-type cfs and 9s 178 

 Blood cfs and 9s 156 

 Scarlet cf s and 9 s 70 

 I Blood scarlet cf s and 9 s 50 



2. Scarlet X Vestigial (second chromosome character). 



Fi Wild-type 



Wild-type 312 

 Vestigial 93 

 Scarlet 109 

 Vestigial scarlet 38 

 This is evidently a 9 : 3 : 3 : I ratio. 



3. Scarlet X Sooty (third chromosome character). 



Fj Wild-type 

 Wild-type 611 

 Scarlet 265 

 Sooty 284 

 Scarlet sooty o 



4. Scarlet X Eyeless (fourth chromosome character). 



Fi Wild-type 

 r Wild-type 



Scarlet 

 Fi < 



I Eyeless 



[ Scarlet eyeless 



Among the F 2 of this cross appeared the new eye color which 

 has given rise to the strain called rose. This new eye color was 

 later found in the eyeless stock itself. 



The exact linkage relations of scarlet were next determined 

 by mating scarlet to sooty and to dichaete, and back crossing the 



