196 GENETICS 



present only a single determiner for excess ear-length, 

 with ordinary short-eared rabbits having no excess 

 ear-length, in order to see if the expected Mendelian 

 three-to-one proportion for a monohybrid would ap- 

 pear in the progeny. 



10. HUMAN SKIN COLOR 



Finally, although accurate published data is 

 wanting, it is probably true that skin color in all 

 kinds of hybrids resulting from crosses between 

 negroes and whites is not a case of blending inherit- 

 ance, as commonly supposed, but rather of true 

 Mendelian segregation. In fact, there is frequently 

 visible evidence that segregation does occur, as shown 

 by many authentic instances where the offspring 

 of diversely colored parents produce children with 

 skin color of different shades. 



If human families included hundreds of offspring 

 in a single generation instead of the usual number, 

 the problem of skin color in man could doubtless 

 be quickly solved since ratios could then be obtained 

 large enough to reveal the underlying laws of inher- 

 itance. 



