IN THE SECOND CHROMOSOME. 



821 



Comparison of table 18 with table 14 will show tlmt tlic n>MiItH 

 C C 

 given by ;^ and by Cjji arc almost if not (luite the Kiiine. 



C 



11 r 



That is, homozygous Cn , gives the same result as no Cu ,. 



HOMOZYGOUS C/y .-WITHOUT Cji ,. 

 b Pr Ctt 



A female 



b Pr cm 

 was mated to a male 

 see above. 



Jli lLi.\ 



h p, c rrirj 



Clir s 



(a cross-over from G99, q. v., 



U Pr tjir Sp 



Six wild-type daughters were tested by milling to 



b Pr c Sp males. Four gave the expected result for —^ •' females ; 



and two (745 and 748) gave no curved offspring, so that they must 

 have been r 7^ — - — - . 



b Pr Ciir 



Females 885 to 888 contained a *S' 6 Cn r chromosome dorivod 

 from the pr~^ experiments and a Pr Cur s„ chromosome derived 



from a stock culture that came from culture 570 {q. r., p. 314). It is 

 quite possible that some or all of these females carried another gene 

 affecting crossing-over (Cju, u — see below) ; but the results have 



Cllr 



Table 19.— 



C 



II r 



Table 20. 



been included because they are the only ones available for S' in the 

 presence of homozygous Cu r- Other work done with Cm, u makes it 

 probable that this gene would not seriously affect any region except 

 that from purple to curved; and the purple speck values for this 

 experiment agree with those from 745 and 74S. TluTcfore the two 

 results are probably comparable. Both are inclucknl in tables 19 and 

 20 and the last line of figure 1. 



'May contain Cni, //• 



