Color inheritance in the Horse. 



15 



He finds it also inherited as a distinct unit although fluctuating in 

 its limits. It is a spreading of white over the back, sides and croup, 

 and down onto the legs. It is dominant and may appear with any 

 color so far discussed. It is apparently what the horse breeder calls 

 piebald or skewbald or what the average person calls a "calico" horse. 

 Albinos are uncommon, but extreme spotting with blue eyes (glass 

 eyes) are frequently seen. 



The reduction of Pigment in Mane and Tail. 



Yellow manes and tails on sorrels and cream colored extremities 

 on duns are very common. They are apparently recessive since one 

 chestnut mare Bessie at the Iowa State College has produced eight 

 chestnut colts, six with manes the same color as the body, two with 

 the yellow mane. Another chestnut mare known as the "half-hackney" 

 bred qualitatively the same producing two colts of the first class 

 and one of the second. Four chestnut mares with yellow manes 

 mated to three different chestnut stallions with yellow manes produced 

 thirteen foals with yellow manes. The summary of data on this is 

 appended. 



Chestnut stallions 

 without yellow manes 



Chestnut stallions 

 with yellow manes 



Chestnut mares with yellow manes . . . 

 Chestnut mares without yellow manes. 



25 wdthout 6 with 

 17 without 2 with 



I 



13 with 

 19 without 3 with 



This shows it apparently to be recessive. A cream colored mare 

 with light mane and tail produced three dun colts with black extremities 

 when crossed to a bay. This would fit the above hypothesis although 

 it throws no light on it. 



The dilution factor. 



The dilution factor I is apparently dominant. Mouse is a dilute 

 form of black and three matings of mouse to black have given two 

 mouse-colored and one black. The mouse colored parent of the black 

 was produced by a black stallion to a dun mare so was known to be 

 heterozygous. The table shows that duns mated to other colors have 

 produced 13 duns to 19 other colors, near enough to expectation in 

 such small numbers to account for dilution being a dominant factor. 



