178 ANIMAL LIFE AND HUMAN PEOGEESS 



Then the original cross means the union of a gamete 

 (AA'-A^) containing all three factors with one (aa^a^) that 







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contains none of them. The first cross contains a single dose 

 of each of the three factors and is, on hypothesis, exactly inter- 

 mediate in size between the two parents. Such an animal. 



