THE INHERITANCE OF BLACK-EYED WHITE 

 SPOTTING IN MICE 



C. C. LITTLE 



Black-eyed white varieties of rodents have long been 

 recognized and used as material for genetic investigation. 



Cuenot, Morgan and Durham with mice and Castle with 

 guinea-pigs have utilized this particular color variety in 

 breeding experiments. For the most part they are agreed 

 that black-eyed white varieties represent an extreme con- 

 dition of the ordinary "spotted" or " piebald" series. 



Cuenot (1904) in treating the inheritance of spotting 

 concludes that there exists a continuous series of partially 

 pigmented forms extending on the one hand from mice 

 with white on the tail, or with a small white ventral patch, 

 or with small white forehead spot, through a series of 

 decreasingly pigmented forms until the black-eyed white 

 form is reached at the other end of the series. As to a 

 factorial explanation for the phenomena observed in the 

 inheritance of spotting, Cuenot feels that there are nu- 

 merous stages of the spotted condition (P) which he desig- 

 nates by p 1 , p 2 , p 3 , p 4 as progressively whiter forms are 

 considered. He believes, however, that the details of 

 spotting are not represented in the germ cell. He further 

 mentions the failure to obtain any particular stage of 

 spotting in a true breeding condition. Selection of nearly 

 solid-colored forms has enabled him to obtain animals 

 with greatly increased white areas. 



Durham (1908) has obtained some evidence for two 

 different types of spotting, one recessive to solid-coated 

 forms and one dominant to them. She has reported sev- 

 eral crosses which I have considered in more or less detail 

 in another paper (Little, 1914). None of the crosses pre- 

 sented by her can be considered as critical tests of the 

 presence of two distinct spotting factors. Morgan ( 1909 ) , 

 727 



