The Genetic Factors in the Development of tile Housemouse, etc. 127 



Now as to the agoutis. In all thirty-onr agoutis (chiefly females) 

 have been tested by mating them to four albino males known to be 

 without G (known to give no agoutis when mated to black). These 31 

 agoutis have produced 49 families, with 181 young. Of these young 

 there were 94 blacks and 87 albinos, and not one single agouti. This 

 proves that in this family the factors a and G never went into the 

 same gamete. 



This is the only instance of mutual repulsion of factors (spurious 

 alellomorphism) in mice I know of, and I think it is the more remar- 

 kable because here the repulsion existed between two factors which 

 ordinarily behave quite normally in respect to one another. 



Tables showing the independant transmission of several 

 factors : 



Mutual independance of factors A and B. 



I. Mating of chocolates heterozygote for both A and B (AaBbccDD 

 EEFFggHHLL) to albinos of orange parentage (aabbccDDEEFFggHHLL). 



In 25 litters from such matings there were born: 



30 Chocolate (AB), 26 Orange (.\b). and 56 Albino (aB) and (ab) 

 Calc: 28 ,, ,, 28 ,, ., 56 



II. Mating of agoutis heterozygote for both a and B (AaBbCCDD 

 EEFFGGHHLL) to albinos of yellow agouti parentage (aabbcCDDEEFF 



GGHHLL). 



In 17 litters from such matings there were born: 



19 Agouti (AB), 15 Yellow agouti (Ab), and 39 Albinos (aB) and (ab) 

 Calc: 18.25 ,, ,, 18.25 .• ■. •. 36.5 ,, 



Mutual independance of factor A and c. 



III. Mating of blacks heterozygote for both A and c (AaBBCcDD 

 EEFFggHHLL) to albinos of chocolate parentage (aaBBccDDEEFFggHHLL). 



In 34 litters of such matings there were born : 



32 Black (AC), 41 Chocolate (Ac), and 76 Albinos (aC) and (ac) 

 Calc: 37.25 ,, ,. 37.25 ,, ,, 74.5 



IV. Mating of agoutis heterozygous for A and c (AaBBCcDDEEFF 

 GGHHLL) to albinos of cinnamon parentage (aaBBccDDEEFFc;GHHLL). 



In 13 litters of such matings there were born: 



17 Agouti (AC), 16 Cinnamon (.\c). 28 .\lbinos (aC) and (ac) 

 Calc: 15.25 „ „ 15.25 „ „ 30.5 ,, , ,, ,, 



