INHERITANCE OF COAT-COLOUR IN RABBITS. 



By R. C. PUNNETT, M.A., F.R.S. 



CONTENTS. 



PAGE 



Introduction . 221 



General scheme of the experiments 222 



The Fi generation 223 



The F2 generation 223 



Agouti from black x black 225 



The Hypothesis 227 



The Fs generation ........ 229 



The synthesis of agouti bearing blacks .... 233 



The test of the coupling between D and E . . . 234 



The chocolate series ........ 235 



The Himalayan pattern 236 



Introduction. 



When the following experiments were started ia 1907 we were 

 already familiar, through the work of Castle (1) and Hurst (.5). with 

 certain phenomena in the inheritance of coat-colour and pattern among 

 rabbits. These investigators had shewn that the wild grey, or agouti, 

 is dominant to black, and that these tw(j full colours are respectively 

 dominant to the two dilute forms, yellow and tortoise (= the " sooty- 

 yellow " of Castle). Moreover with regard to pattern Hurst had 

 published a brief statement (6) to the effect that Dutch marking is 

 recessive to self-colour, the heterozygote being variably marked, and 

 that the Himalayan pattern is recessive to the self-coloured form. 

 Castle also(l) had given an account of a few experiments with the 

 Himalayan in which this form was shewn to be dominant to the pure 

 albino. 



More recently (1909) Castle has published a general account (3) of 

 the colour varieties in the rabbit that have so far been analysed. With 

 that account m}' own work is iu general agreement, and in so far as is 

 possible I have adopted his system of nomenclature for the various 

 factors concerned'. 



' Of the four colour varieties agouti, yellow, black, and tortoise, the two former are 

 regarded as containing the agouti factor A which is absent from the black and the tortoise. 

 The agouti and black again differ from the yellow and the tortoise in containing a factor 

 E for the extension of the pigment. Melanic pigment occur.s also in the tortoise and the 

 yellow but in much smaller amount and is chiefly localised in the nose, ears, tail, and 

 feet. 



Journ. of Gen. 11 16 



