CHROMOSOME THEORY OF INHERITANCE 333 



When a hybrid is crossed with a recessive, the gametes of the 

 hybrid will be half dominant and half recessive, while the gametes 

 of the recessive will all carry the recessive gene. 



T >t 

 Formula. X =:n Tt > u > u 



I* ^ T> 



Results are half recessive and half hybrid. 



HEREDITY IN ORGANISMS 

 KIND OF ORGANISM DOMINANT CHARACTER RECESSIVE CHARACTER 



Wheat Late ripening Early ripening 



Wheat Susceptibility to rust Bearded 



Barley . . . . Beardless Immunity to rust 



Maize Round, starchy 



kernel Wrinkled, sugary kernel 



Cotton Colored lint White lint 



Sweet pea Colored flower White flower 



Cattle Hornlessness Horns 



Rabbits Short fur . . . . Angora fur 



Mice Pigmented coat White coat 



Leghorn chickens . . White plumage Pigmented plumage 



Canary Crested head Plain head 



Land snail Plain shell Banded shell 



Horses Black Chestnut 



Bay Black or chestnut 



Gray To all colors 



Man Curly hair Straight hair 



Dark hair Light ; red 



Brown eyes Blue eyes 



Normal pigmentation Albinism 

 Broad fingers (lack- 

 ing one joint) .... Normal length 



QUESTIONS AND SUGGESTIONS 



1. Contrast somatic variations with germinal characters. 



2. Diagram, using the Punnett square, the Andalusian fowls through 

 two generations. 



3. Diagram, using the Punnett square, the Japanese four-o'clocks 

 through two generations. 



