MUTATIONS IN EYE-COLOR OF DROSOPHILA. 



Records by Separate Bottles A, B, C. 



325 



Red 9 X Pink <? 



in F«. 



Bottle 



A 

 B 

 C 



9 



Red. 



Pink. 



162 



80 



178 



Total 



420 



<? 



Total. 



Proportion of 

 Red to Pink. 



Total. 



51 

 14 

 39 



104 



The expectation is 3 Red to one Pink. The average result is 4.2 to 1 . The three 

 bottles gave different ratios; one, A, giving 3.3 to 1. 



The converse cross is as follows : 



P 9 by R <? 



Red 9 

 Redd" 



Red 9 733 



Red <? 589 



Pink 9 189 



Pink <? 140 



Records by Separate Bottles A, B, C. 



9 



o" 



Bottle. 



A 

 B 



C 



Red. 



Total. 



Pink 



Red. 



Pink 



Proportion of 

 Red to Pink. 



Total. 



Red. 



Pink 



268 



141 



324 



62 

 51 

 76 



273 



58 



258 



Total 



733 



189 



62 

 12 

 66 



589 



140 



124 



63 



136 



323 



Here also the expectation is 3 to 1 . The average result is 4 to 1 . One cul- 

 ture-bottle, B, gave, however, 3.2 to 1. 



In order to examine the problem more closely, the offspring of Fi pairs were 

 recorded separately. The next table gives the data for one of the crosses. 



F x Pairs out of Red 9 X Pink o*. 



Bottle 



9 



Pink 



10 



20 



9 



2 



5 



8 



21 



21 



2 



13 



20 



7 



4 



19 

 161 



Red. 



42 

 69 

 59 

 18 



23 

 34 



57 

 65 

 9 

 34 

 42 

 30 

 24 

 _62 



568 



<? 



Pink. 



~~8~ 



13 



18 



4 



8 



6 



29 



22 



7 



17 

 17 

 11 

 8 

 18 



186 



Total. 



105 

 181 

 146 



45 



53 



87 



189 



192 



34 



114 



134 



80 



68 



136 



Proportion of 

 Red : Pink. 



5 



4.5 



4.4 



6.5 



3 



5.2 



2.8 



3.5 



3 



2.8 



2.6 



3.5 



4.6 



2.5 



1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 



1 + 



1 



1 

 1 

 1 



1 





