176 Inheritance of Coat Colour in Mice 



These results suggest that sable is recessive to yellow. But at the 

 same time it seems extraordinary that some of the sables should be 

 able in their turn to throw yellows, and at present no adequate 

 explanation is forthcoming. The fact that there is probably more than 

 one kind of sable may supply the basis for explanation, but the question 

 ought to be more fully worked out. 



Sables, like yellow mice, show a tendency to become abnormally fat. 



Besides obtaining ordinary sable mice, another form appeared un- 

 expectedly in my experiments. These I called reversed sables, because 

 in them the agouti pattern was reversed. The base of the hairs was 

 yellow and the barring was black or chocolate. 



This marking was only apparent in the young mouse; after about 

 6 months these mice moulted completely yellow, but it was a very con- 

 spicuous feature in early life. 



I twice obtained mice which were agouti all over with the pattern 

 reversed. They behaved exactly like sables and never threw any 

 agouti young. 



Matings between sables in which the reversed sables appeared gave 



49 sables, 21 reversed sables, 19 yellows, 41 other colours. 



Matings between sables and other colours, not yellow, in which 

 reversed sables appeared, 



12 sables, 12 reversed sables, 9 yellows, and 29 other colours. 



The reversed sables are recessive to the other sable, mated together 

 they produced reversed sables and other colours but never ordinary 

 sables, and mated with ordinary sables did not produce reversed sables. 



Sables which could throw reversed sables when mated with reversed 

 sables, gave 



10 sables, 8 reversed sables, 5 yellows, and 18 other coloured mice. 



Owing to the great variation which obtains amongst sables, it has 

 not been possible to classify them very satisfactorily. 



Matings between dark sables (broad dorsal streak) x light sables 

 (narrow dorsal streak) gave 



8 dark sables, 3 light sables, 10 other colour. 



Dark sable by yellow gave 



10 dark sable, 5 light sable, 8 yellow, 8 other colour. 



Sable X agouti gave 



7 sable, 7 yellow, 17 agouti. 



