OF MUTANT CHARACTERS. 



213 



per cent were antlered and antlered-like. That is, about 36 per cent 

 of the vestigial-antlered compound males were longer than vestigial 

 (table 58). The percentage of antlered dominance in F 2 (36 per cent) 

 was the same as that observed in FI (36.9 per cent). 



One other experiment was made in 1913 and repeated in 1915, 

 namely, the cross of antlered male to black vestigial female carried to 

 F 2 (table 59). In the FI females there was a slight amount of antlered 

 dominance (6 per cent) and among the males very much more (57 

 per cent). 



TABLE 59. PI, antlered cf X black vestigial 9 . 



The F 2 cultures raised in 1913 agreed closely with the classification 

 of 25 pair cultures made in 1915 by Morgan. Together these F 2 

 cultures gave 3,941 flies, of which 1,742 or 44.2 per cent were antlered 

 or antlered-like. That is, besides the homozygous antlered, 38.4 per 

 cent of the vestigial-antlered compounds could be separated from the 

 vestigials, though not from the antlered. Among the females the ant- 

 lered dominance was 23 per cent and among the males 58 per cent, 

 which is in agreement with the 57 per cent observed in the FI males. 



A rough calculation of the amount of crossing-over between black 

 and antlered was made, as follows: There were in the experiment 44.2 

 per cent of antlered flies where only 25 per cent would have been expect- 

 ed if antlered were a strict recessive. That is, 19.2 per cent (44.2 25) of 

 all the flies (3,941) or 757 flies were due to antlered dominance. There 

 were 132 black antlered flies, all of which were due to antlered domi- 

 nance and all of which were cross-overs between black and antlered. 

 In the total of 757 comparable flies, 132 or 17.4 per cent were cross- 

 overs, which agrees remarkably with the mapped black vestigial 

 distance of 17.5. 



Just as in the case of strap, all the data point to the allelomorphism 

 of antlered to vestigial. The vestigial-antlered compound is in the 



