Y. Tanaka : Sexual Demobphism op Gametic Series in the Keduplicatiox. g3 



Gametic Coupling. 



Somewhat fully studied cases in the field of the conx^ling-reduplication are 

 the moricaud-yellow and the striped-yellow coupling. In these the gametic series 

 are 



Ab aB ab 



1:1:2 



t 



^'"1:1:3 



? 1 : 1 



If the male series is 2 : 1 : 1 : 2, the F., zygotic series will be 8 : 1 : 1 : 2, 

 and if the 3:1:1:3 is the case with male gametes, the F2 ratio will be 

 11 : 1 : 1 : 3. So far as the breeding is confined to themselves the actual 

 feature of the gametic distribution under consideration will not be revealed 

 because the ratios 8:1:1:2 and 11 : 1 : 1 : 3 are not practically remote from 

 the zygotic series which would be produced by the ordinary 4:1:1:4^^ and 7 : 

 1:1:7"^ systems respectively. The clear analysis of tlie case was accomplished 

 by crossing the diheterozygous animals with the double recessives reciprocally. 



The 9:3:3:1 Ratio derived from the Reduplicated 



Gametic Series. 



The reduplicated gametic series do not necessarily give rise to an abnormal 

 zygotic distribution, but the apparently normal 9:3:3:1 ratio may some- 

 times be produced l^y them. 



In the cross Aabb ? x AaBb S, where the female produces two forms of 

 gametes while the male gives four possible gametic combinations, the AaBb form 

 in the subsequent generation may be produced by union of the gametes ab and 

 AB as well as by that of Ab and aB. In the AaBb female which resulted 

 from fertilization of ab-egg by AB-sperm there will occur, as stated in the 

 preceding lines, a complete coupling between A and B ; in the AaBb male 

 derived from fertilization of Ab-egg by aB-sperm, on the other hand, there will 

 exist a low partial repulsion, say 1 : 3 : 3 : 1. If in interbreeding of the A-B- 

 offspring ex Aabb ? X AaBb J, the male and the female such as above mentioned 

 chanced to be brought to mating, that is, if the gametic series in the couple were 



1) The resulting zygotic series is G6 : 9 : 9 : 16 that is 7.33 : 1 : 1 : 1.78. 



2) The resulting zygotic series is 177 : 15 : 15 : 49 that is 11.80 : 1 : 1 : 3.27. 



