160 



I'll YSIOLOCK \\L CENETICR 



deposited in a rabbit's hair is constanl for a given genotype. 

 Therefore, the phenotypic expression is correlated to the length 

 of the hair. Longer hair showing more diluted color. 



,cc 



ks-.lt 



C K C 



df^d 



c a c 



C r C' 



c a c l 



Fig. 32. — Action of color factors in the guinea pig. The average grades of 

 sepia (solid) brown (dot and dash) yellow (dash) found with particular combina- 

 tions of factors of the series Fj, P, and B with the five homozygotes of the albino 

 series. Factor E is used to indicate reference to black parts of the fur, and e to 

 yellow parts of the fur. (From Wright, 1927, Genet. 12, Fig. 8.) 



In connection with this work, another type of genie interaction 

 which has been studied in rodents may be mentioned, and the 

 related facts might also find their place in the chapter on domi- 

 nance. One Mendelian character in rodents upon which much 

 work has been done since the first studies by Cu£not is Spotting 

 in its different aspects. Spotting is usually caused by a major 



