Crossing Over and Chiasma 



119 



FIGURE 16-3 {Left). General- 

 ized form of Figure 16-2. See 

 text for details. 



EGGS SPERM ZYGOTES 



Frequency I Genotype Frequency i Genotype Phenotype 



o + / a + .50 " + + 

 a + / + b .25 " a + 



.5-p 



.5-p 



V 



a + / + b .25 " + b 

 + b / + b 



a b / a + 



a b/ + b 



+ + / a + 



+ + / + b 



\. 



FEMALES 



^ + / + w 

 y + / + cv 

 y + / + ct 

 y + / + m 



y + / + f 



a b 



\ 



% CROSSOVER 

 CHROMOSOMES 

 AMONG SONS 



1.5 



^' 



■ u 

 20 



• \ 

 34 



48 



FIGURE 16-4 (Right). Crossover 

 percentages between one gene and 

 others linked to it. 



