OLD TYPES AND NEW 



195 



If heterozygous brown-eyed individuals mate, there 

 is one possibility in four that their offspring will have 

 blue eyes unlike their own, but like the two blue-eyed 



Grandfather Grandmother Grandfather 



Grandmother 



Homozygote Hobiozygote 

 . Duplex^ NuUiplex 



Heterozygote 

 Simplex 



Homozygote 

 Duplex 



Heterozygote 

 Simplex 



Homozygote 

 Nulliplex 



FIG. 44. Three generations of a Mendelian monohybrid. The 

 outlines represent the somatoplasms with the phenotypic 

 character on the outside. The black symbols inclosed within 

 the somatoplasm stand for the germplasm in the form of 

 gametes. The short dotted arrows indicate the relation be- 

 tween germplasm and somatoplasm. The long dotted arrows 

 indicate possible recombinations of germplasms. 



grandparents. Such a blue-eyed child would be an 

 instance of atavism. The explanation of this appar- 

 ently inconsistent hereditary behavior is perfectly 

 simple in the light of the Mendelian ratios, as shown 



