M\ AM A 



^9^ 



females (series 3). The F^ eggs laid by the tirst and the second series 

 of raatings will be all D batches, since all females are DR or DD. For 

 the same reason, the third series of matings will give all R batches. 

 The Fj eggs derived from the F^ moths paired inter se will be, therefore, 

 a mixture of D and R batches in certain proportions. If we assume 

 that the number of males and females found in each batch is nearly the 

 same, the proportion of D and R batches laid by inter se moths derived 

 from an F^ D batch would be 6/> : 3-K or 2D : IR. 



As in the case of the F^, the zygotic constitution of F3 D and R 

 batches is not simple D or R. As the formulae quoted just above shew, 

 the constitution of certain F^ D batches is DD (series 1 a), some batches 

 DR (series 1 c), some a mixture of DD and DR (series 1 6 and series 2 a), 

 or DR and RR (series 2 c), and the rest DD, DR and RR (series 2 b). 

 We get similar results in the case of the F3 R eggs, some batches being 

 DR (series 3 a), some (series 3 c) RR, and the rest (series 3 6) a mixture 

 of DR and RR. 



If moths derived from F3 D or R batches were inbred, what will be 

 the result in the dominant series ? 



In F3 D batches, as we have already observed, there are five different 

 kinds of batches whose zygotic compositions are respectively : (1) DD, 

 (2) (DR + DD), (3) DR^ (4) {DD + DR + RR), (5) (DR + RR). The 

 moths derived from each kind paired inter se will produce the following 

 Ft batches : 



Joam. of Gen. 11 



27 



