392 Maternal Inheritance and Mendelism 



allelomorphism ; and (3) in certain generations, both parental character- 

 istics even when inbred give rise to the antagonistic characteristics 

 which at first suggests that there is a departure from the normal rules. 



Suppose, now, there are certain Mendelian characteristics which 

 behave as maternal in ioheritance. If they were reciprocally mated, 

 what would be the result as regards their offspring ? Let D represent 

 a dominant and R a recessive factor, the results of their reciprocal 

 matings would be diametrically opposite. In the case of a i) female 

 mated with an R male, the resulting F^ eggs would be all D, while an 

 R female mated with a D male would give all R F^ eggs, in spite of 

 their zygotic constitutions being the same in both matings, namely, DR. 

 And therefore, all the worms and moths derived from the F^D ov R eggs 

 will have the constitution DR^ in which the D behaves as an active 

 factor in determining their characteristics. In the same way the egg- 

 cell which has the composition of DR during its development in the 

 parent body is influenced by the D factor only, and consequently 

 after segregation, when it lost the antagonistic factor and became pure 

 D or R, it retains the D characteristic before acquired. Thus the results 

 of fertilization will be the production of all normal-coloured ^2 batches. 



Zygotioally considered, however, the F^. D eggs are not the same in 

 their constitution. As the result of the fertilization, some of them will 

 be DD, some DR and the rest RR. Consequently, the constitution of 

 the F^ moths derived from the F^ D eggs will be a mixture of DD, DR 

 and RR» Thus all the F^ eggs, whether fertilized with D ox R sperma- 

 tozoon, will be all D characterized. 



As there is no means in this case of distinguishing a DD worm or 

 moth from a DR or an RR, random matings between them are expected 

 to occur. The result will be as below : 



Colour of the Zygotic composition 



Fi eggs laid of the egg 



a. ? DD X <? DD = D DD 



b. ^ DD X d DR = D (DD + DR) 



c. 'i DD X s RR = D , DR 

 a. ^ DR X i DD = D [DD + DR) 

 h. 'i DR X 3 DR = D (DD + DR + RR) 

 c. f DR X 3 RR = D (DR + RR) 



a. ^ RR X s DD = R DR 



b. 9 RR X 3 DR = R (DR + RR) 



c. ^ RR X i RR = R RR 



In some cases female DD moths will mate with DD, DR or RR 

 males (series 1), in some others DR females will mate with the same 

 three kinds of males (series 2). The same holds good in the case of RR 



