STUDIES ON HKJH AND LOW NON-DIS.IUNCTION 



87 



TABLE 4. 



Further générations of female-exceptions from hiyh non-disjuncti(n) 



cultures when mated by various males. 



Percenta<iie of exceptions 21,44 i 1,25. 



Common percentage of exceptions from tables 1—4 22,28 ±, 0,62, 



As is seen immediately the percentage of exceptions from the 

 tables 1 — 4 all have the same order of magnitude and from this I 

 concluded that neither the Y nor the autosomes may influence the 

 percentage of exceptions. I have therefore in the following experiments 

 not paid much attention to the constitution of the males to which 

 I have crossed the exceptional females. It \vould however have been 

 better in order to test the influence of the X only always to cross these 

 females to males from unrelated stock, since we than could have been 

 quite sure never to get exceptional females homozygous with respect 

 to the autosomes of the high non-disjunctional stock. There is namely 

 the possibility, that although the X:s from the high non-disjunctional 

 stock (which in the following may be denoted by X) alone may be 

 responsible for the high percentage of exceptions, when these X:s are 

 not present the females which are homozygous with respect to the high 

 non-disjunctional autosomes also may produce a percentage of excep- 

 tions higher than the ordinary as a consequence of autosomal genes (in 

 the same sense as for instance there are autosomal genes which pro- 

 duce the same eyecolor as do sex-linked genes). Some of the results 

 may therefore be looked upon as merely alternative. 



Now when taking regular daughters from high non-disjunctional 

 cultures and crossing them to various males the A'A'F-females always 

 produce a low percentage of exceptions (table 5) which makes it clear 

 that point 5 viz. the assumption of a cytoplasmic »factor» only inheri- 



