98 GERT BONNIER 



to all the chromosomes from the eosin line of high non-disjunction 

 produce a low percentage of exceptions. 



3. The ovarian cytoplasm of the exceptional females from the high 

 non-disjunctional cultures can not ])e responsihle for the high percen- 

 tage for if it were, their regular non-disjunctional daughters should 

 always produce the high percentage of exceptions. But from tahles 5 

 and 10 it is clear that this is not so. 



4. In fragmenting the original X:s and making up non-disjunc- 

 tional cultures, where the exceptional females are homozygous with 

 respect to different parts of these A': s it has been possible to produce 

 a number of different percentages of exceptions all of which lie 

 between the ordinary low percent and the high percent from the eosin 

 line of non-disjunction. 



Concerning the last point one might suggest that it is some in- 

 fluence from the autosomes or the Y-chromosome which makes the 

 percentage higher than the ordinary low percentage. But as a matter 

 of fact there are a great number of instances recorded in the tables of 

 the foregoing chapter where the exceptional females have been at the 

 most heterozygous with respect to the autosomes from the high non- 

 disjunctional line and having another Y-chromosome. Thus it seems 

 to me that one may infer that neither the Y-chromosome nor the auto- 

 somes of the eosin line has any influence upon the exception percen- 

 tage. But as I mentioned in the introduction it seemed to me to be 

 clear from the first crosses made that the whole force which produce 

 the high percentage originates from the X and that I therefore did not 

 pay sufficiently great attention to the source from which the autosomes 

 and the Y-chromosomes of the tested females originated. Thus finally 

 I concede that I have no complete and absolutely conclusive proof that 

 the autosomes and the Y-chromosome are without influence upon the 

 percentage of exceptions in the eosin line but the data from my tables 

 makes it at least highly probable that it is so. 



Of the different possibilities enumerated at p. 84 only two remain 

 which may be used to explain the high percentage, viz. the possibility 

 of a gene or genes in the X (which thus must be recessive) or the 

 possibility of something else in the X. 



If it was a recessive gene in the A' which was responsible 

 for a percentage higher than the ordinary one than in all experiments 

 where we have found such a higher percentage we had to find a 

 common piece of the X with respect to which the exceptional females 

 were homozygous. But as a matter of fact there are instances in which 



