Occurrence of different systems 



of gametic reduplication in male and 



female hybrids '. 



By Y. Tanaka, 



As. Prof, in the University, Sapporo, Japan. 

 (Eingegangen am (J. März 1914). 



In the previous paper-) I have pointed out six cases of gametic 

 reduplication observed in crossing experiments with various strains of 

 Bomhyx mori. Further investigations were made during the seasons 

 last spring and summer, in which some complicated but interesting 

 results were obtained. 



The gametic distribution is generally assumed, so far as the in- 

 heritance was not sex-limited, to follow an identical system in both the 

 sexes. This general rule seems, however, not applicable to certain cases. 

 In my experiments the results obtained up to the summer 1913 all 

 point to the conclusion that the reduplication between certain 

 factors follows distinctly different systems in both sexes, a 

 low partial taking place in the male, while a complete redupli- 

 cation exists in the female. The present paper deals with this striking 

 phenomenon relating to the both genetics of sex and gametic reduplication. 



The marking and colour characters and the strains concerned to 

 the present experiments are as follows^): 



') Read before the Darwin Society held at Tokyo, Nov. 2.3, I'.ilH. 



') Gametic coupling and repulsion in the silkworm. Journ. of Coll. Agric, 

 Tohoku Imp. Univ., Sapporo, Vol. V, Pt. 5, 191.3, pp. 115-148. 



') As to the detailed statements of the markings and colours of the silkworm 

 refer to Toyama (Biol. Centralbl., XXXII, 1912, pp. 593-607) and Tanaka (Journ. 

 of Coll. Agric, Tohoko Imp. Univ., Sapporo, Vol. V, Pt. 4, 1913, pp. 91-113). 



