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IMiana University Studies 



curve are significant. One of them is in the first chromo- 

 some and the other is probably in the third. 



10. While the evidence from my own experiments sup- 

 ports the multiple factor interpretation, I do not wish to say 

 that a gene is a fixed thing incapable of variation. In fact, 

 the numerous multiple allelomorph systems already described 

 show that genes do vary, but they further show that these 

 variations are mutations. 



11. One of the factors for extra bristles was no doubt 

 present at the beginning of the experiment. The others 

 probably occurred as mutations during the progress of selec- 

 tion. 



12. "Extra bristles" is partially dominant to the normal. 



