No. 611] 



ALLELOMORPHS 



691 



cessive to fertility, and the seeds resulting from partial 

 fertility of sterile plants again give segregating families. 

 In Family A, which shows an exceedingly slight fertility 

 of sterile plants, the segregation ratio in the offspring 

 derived from fertile individuals is quite close to expecta- 

 tion, but in Pkmily B which shows a considerably higher 

 grade of partial fertility of sterile plants, the progeny of 

 fertile individuals exhibit considerable deviations from 

 the expected segregation ratio. 



TABLE I 



The Segregating Families, A and B, in 1912 



26.53 2.94 



TABLE n 



(a) The Prosienii of the Fertile PU 



pothesis. The dominant and the recessive types con- 

 cerned are assumed to be transformed by certain un- 

 known causes into the other allelomorph. The recessive 

 allelomorph which has made its appearance in Families 

 A and B is assumed to have originated in the preceding 



