HEREDITY AND VARIATION 



Zygotes from 

 which Pj 

 developed 



Gametes 

 of Pi 



Zygotes from 

 which Fj 

 develops 



1 heterozygous gray 



1 homozygous white 



Fig. 6.12. A cross between a heterozygous gray mouse and a homozygous white mouse. The 

 diagram illustrates the segregation of a pair of genes when their carriers, a pair of homologous 

 chromosomes, undergo disjunction; notice the possible combinations that can occur between 

 gametes. W, gene for gray coat color; w, gene for white coat color. 



Zygotes from 

 which Pi 

 developed 



Gametes 

 of Pi 



Zygotes from 

 which F-[ 

 develops 



1 homozygous gray 



1 heterozygous gray 



Fig. 6.13. A cross between a homozygous gray mouse and a heterozygous gray mouse. The 

 diagram illustrates the segregation of a pair of genes when their carriers, a pair of homologous 

 chromosomes, undergo disjunction; notice the possible combinations that can occur between 

 gametes. W, gene for gray coat color; w, gene for white coat color. 



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