Yellow YY .Oreenyy 



Round RR Wrinkled rr 



4 



■Yy 

 / 



Yy 



\ 



YY 



Yy 



yY yy 



Above are diagrams of two of Mendel's experiments 

 with monohybrids. At the left the characters of yel- 

 low color of seed ( F) and green color of seed {y) are 

 carried by the gametes of the (P) parent generation ; 

 at the right, smooth surface of seed {R) and wrinkled 

 surface of seed (r) . In the next (Fi or first filial) genera- 

 tion, flowers produced by the hybrid seed are mated 

 ^-ith flowers from hybrid seed of similar parentage. 

 Explain characters of the F2 generation from text. 



The dihybrid carries two pairs of characters. Thus the plants of the Fi generation 

 have received from the chromosomes of the parents both characters of color and char- 

 acters of seed surface and are mated with each other. In the F2 generation all four of 

 the characters appear or are segregated out in the proportion of 9-3-3-1. Arrange 

 the characters as single pairs and place them above and at the side of a series of 

 squares, combine them in the squares, and you can predict the proportions of the' 

 F2 generation in a dihybrid mating. 



386 



