CASTLE. — LAWS OF HEREDITY. 



235 



A. A{D). 



2 A X /I, yielding offsprinc: 2 



4 .4 X ^(C), yielding offspring 2 + 2 



B. 



2A{D) X A(B), yielding offspring 



+ 



1 + ^ 



Total 41 + 



+ \ 



or 9 ^ : Q) A{B): 1 B. The offspring in this generation are j;}, or 

 93.7 per cent, of the dominant form. Calculating in a similar way for 

 the next four generations, we find that the proportion of dominant indi- 

 viduals steadily increases. The complete series for generations 1-8 fol- 

 lowing the cross between a pure A and a pure B is shown in Table III. 



TABLE III. 



Results of Selection for the Dominant Character A in the various 



Generations following a Cross between a 



Pure A and a Pore B. 



Inspection of the table will allow one to continue it to any desired 

 extent.* Compare Diagram on p. 239, B. 



A- + 2 A ' A (B) + A (By^. Treating the progeny of each mating as equal to four, 

 ^ve have a. A (B). B. 



1 mating A y. A, yielding offspring 4 



2 matings .4 X -4 {B), yielding offspring ... 4 + 4 



1 mating ^ (B) X ^ (^), yielding oft'spring .1 + 2 +1 



Total offspring Q A + Q A (B) + B. 



* The percentage of dominant forms in the various generations may be quickly 

 calculated by observing that it equals the series 



1 4. (2)^ - 1 , (3)^ - 1 , (4)^ - 1 , (5)=^ - 1 

 1 "*■ (2)2 "^ (3)2 "^ (4)2 "^ (5)2 ^^^- 



