No. 512] 



NOTES AND LITERATURE 



499 



So long as gray is bred to gray each chat', 

 its allelomorph ; ^, ^, ^. But each gei 

 only one C, one G, one B. Similarly for an; 

 its like. 



If gray (CGB) is bred to chocolate (Cgb) 

 has the composition CGBCgb. Tin- allelmm 

 These hybrids bred together give the result 

 table. The possible genu cells of each will 

 Cgb, which by combination give the resu 

 grays. •'! blacks, 1 chocolate. 





CGB 



gray 



gray 



CGb 

 CGB 

 gray 



CGb 

 gray 



CgB 

 CGB 



CgB 



B 





Thus the black mice th 



generation are due to the absence ot G and to the presence <>t 

 the factor B. The single chocolate amongst the 16 mice is due 

 to the absence of both G and B in the presence of C. Hence, 

 Miss Durham recognizes chocolate (Ch) and color factor (C) 



gray mouse has the strengthening factor F along with C and G. 

 The chocolate mouse has the diluting factor D along with C and 

 F C 



Ch. The combination gives F< '< JIM 'li. 'I he pairs are f) , ^ , 

 Omitting C, present in all combinations, we find the possible 

 combinations are FG, FCh, DG, DCh. Two such mice crossed 

 give the kinds of offspring shown in table on page 500. 



The results are 9 gray, 3 dilute gray, 3 black, 1 chocolate, and 

 these are the actual numbers realized. The dilute grays are 

 grays without black and are known as cinnamon agoutis. W hen- 

 ever F occurs with Ch the combination gives black, whenever D 

 occurs alone with Ch (once) the result is chocolate. 



