16 



Tanaka. 



1910 (P) 



Genealogical table II. 



Nor. wh. (Aojiku) 9 X PI- yel. cf 



1911 (Fl) 



Nor. yel. 

 (H. 5'11) 

 .•!72 (all) 



1912 (F,) 



(1) 



I 



Nor. yel. 



(H. 9' 12) 



1 •-'.'! 



Nor. wli. 

 (H. 1012) 



88 



(2) 



106 



1 



PI. yel. 



(H. 11'12) 



61 



1913 (Fj) Nor. yel. Nor. wli. PI. yel. Nor. yel. Nor. wli. PI. yel. 

 46 28 251 96 184 (all) 



As the preceding pedigrees show, the normal yellows in these 

 series did not necessarily produce three phenotypes, as it should be 

 expected in a complete repulsion, but they often gave only two, or even 

 only one, phenotypic forms in the subsequent generation. The normal 

 wliites, on the other hand, manifested themselves as heterozygous in 

 marking character in a certain mating. These results appeared at first 

 sight much pei-jjlexing and difficult to be explained. Fortunately, 

 however, some crosses were made, in the course of experiments, between 

 heterozygous normal yellows and homozygous i)lain whites, which afforded 

 a clue to the analysis of the case. 



As it was point(Hi out by some authors, luaking crosses between 

 heterozygotes and absolute (with respect of the characters in question) 

 recessives is a simpler, or often necessary, work for a critical study of 

 the gametic distribution in the former. The zygotic series produced by 

 such crosses will represent, as it is evident, the gametic proportion of 

 the heterozygous parent. From this point of view I made several 

 matings between XynY and nijny individuals in reciprocal directions, 

 the results of which aic gi\'('n below. 



