MENDELISM IN DOMESTIC ANIMALS 



475 



hybrids, for hybrids between the Hereford and bison exhibit the typical 

 white-face markings. The F t hybrid between the zebu and Hereford, 

 however, has a broken colored face, as shown in Fig. 206. The early 

 history of the Hereford breed indicates that mottled-faced animals were 

 not uncommon in the foundation stock, and today they are met with not 

 infrequently in grade Hereford cattle. The characteristic pattern of 

 Dutch belted cattle appears, also, to be a dominant character as con- 

 trasted with self-coloration. Another color character, the black of 



FIG. 190. California Favorite, grand champion steer at 1916 International Livestock 

 Exposition. Out of a red Shorthorn cow by a Hereford bull. The Hereford pattern is 

 completely dominant. (Photo from G. H. True.) 



Ayrshire cattle, exhibits sex-limited relations and will, therefore, be dis- 

 cussed in another chapter. The polled character in cattle, as we have 

 pointed out before, is clearly dominant to the horned condition, but the 

 FI may exhibit slight scurs. The breeding of cattle for the polled condi- 

 tion is a simple problem in Mendelism involving a difference in a single 

 pair of factors. The study of other characters in animals, particularly 

 those which are of economic importance from a Mendelian standpoint, 

 has just begun. 



Mendelism in Sheep. As we have already noted the short-eared 

 condition in sheep has been shown to be a simple dominant to the long- 

 eared character. The factor for black wool in sheep is recessive, as 



