44 



Inheritance of Coat-Colour in Rahhils 



Moreovc^r the proportion in which these G forms occurred is that expected 

 on hyjMthesis. The agouti-black % % of the constitution DdEEAaBb 

 must be supposed to produce 8 kinds of gamete — DEAB, DEAb, 

 DEaB, DEab, dEAB, dEAb, dEaB, dEab— while all of the gametes 

 of the chocolate </ are of the type dEab. The result of such a cross 

 is shewn in Fig. 3, and, as Table V indicates, the expectation of the 

 6 classes in the ratio 1 agouti, 1 agouti-black, 2 black, I cinnamon, 

 1 deep cinnamon, 2 chocolate is closely realised in fact. 



Fig. 3. 



It is evident from Fig. 3 that the chocolates (as also the blacks) 

 produced should be of 2 sorts, viz. those heterozygous for D, and 

 those which do not contain this factor. In order to put this to the 

 test two of these chocolates were mated with a homozygous agouti (/" 

 {F 141)'. One of these chocolates [E 239) gave 9 agouti young and 

 was therefore of the constitution ddEEaabb. The other {G 51) 



pre 



luced 2 agoutis and 2 acrouti-blacks. Her constitution must 



therefore have been DdEEaabb. The experiment establishes the 

 fact that an animal which is pure chocolate in appearance can carry 

 the factor D. All the evidence shews that there exists a chocolate 

 series containing the factor D which is strictly parallel to the corre- 

 sponding black series. 



Here mention may be made of a few experiments which I carried 

 out with blue rabbits, from which it is clear that a blue rabbit may 

 carry the factor D in the same manner as a black. Thus a blue doe 

 (i^ 211) was made which, when crossed with the original chocolate buck 

 (cf p. 42), gave 2 blacks, 1 agouti -black, and 1 agouti. Evidently the 

 absence of the factor which turns blue iiito black does not affect the 

 relations of the factor D. 



' With 2 chocolate ? ? this buck gave 1(> agouti young, with a chocolate Himalayan 

 he gave G agoutis, and with an orange ( = dilute chocolate) doe he gave 9 agoutis. No 

 olTs'pring of any other colour were produced and there can therefore be no doubt that in 

 constitution he was ddEEAABB. 



