564 Journal of Agricultural Research voi. xxiii, no. 7 
of black spotting which appears similar to that of the spotted Poland- 
China. Wright comes to the conclusion that the Berkshire and Poland- 
Chinas are genetically black-and-sandy spotted hogs in which, by selec¬ 
tion of minor factors, sandy has been diluted to white and black has been 
extended to cover all the body except the six white points. Such evi¬ 
dence as the writers have with regard to the white points casts no light 
on this interpretation, but the idea seems correct for the black color. 
Aside from the fact that the roans occur regularly as a part of the 
progeny resulting from back-crossing Yorkshire xTamworth F t hogs to 
pure Tamworths (12) and in the F A generation of self white breeds crossed 
with Hampshires (5) nothing definite is known about the inheritance of 
the roaning patem. The Sapphire, the only breed making a feature of 
this pattern is of such recent origin that it does not yet breed com¬ 
pletely true and hence is not suitable for analyzing this character (7). 
Several types of roans have appeared in the course of the experiments to 
be reported upon here but not in sufficient numbers nor with sufficient 
regularity to permit their analysis. As a general rule, roans appear to 
be either self colored or ordinarily spotted at birth, but at about weaning 
time hairs of another color begin to appear and soon produce the roan 
effect, either as a self roan or a spotted roan. 
Two self black breeds are known in England but are not common in 
America and their color behavior in crossing is not known, although the 
black of the Large Black breed has been reported dominant to Tamworth 
red. 
Hampshire black is certainly distinct, genetically, from Berkshire or 
Poland-China black, but whether it is equivalent to self black plus the 
white belt or is a third distinct kind of black is not known (5). 
Self red breeds vary in the intensity of their pigment rather widely 
from a light yellow or sandy to a deep brownish red which almost ap¬ 
proaches black. That these differences in intensity are hereditary seems 
probable, but no definite investigation of this point has yet been made 
except to find that there are two distinct kinds of red with respect 
to the way they react towards self white (79, 20). Self red is reces¬ 
sive to self white, to the wild pattern, and to Hampshire black with white 
belt. Self red is the only type of red which is characteristic of any pure 
breed, but grade and scrub hogs are common which are spotted red with 
black or white or roan in various combinations. 
This general survey of the heredity of swine color, so far as it is 
known, may be briefly summarized as follows: 
Self white. Dominant over all other colors. Probably dependent on a single 
factor. 
White belt. Dominant over all other colors but must depend upon more than 
one factor. 
Immature striping and adult agouti of the wild hog. Dominant over all other 
colors except self white and the white belt. Dominance is not complete. 
Roaning. Appears frequently among descendants of self whites by self reds, or 
of self whites by belted blacks. 
Self black. Dominant to self red. 
Black spotting on a lighter ground color. The most frequently occurring type of 
black in ordinary market hogs and therefore probably dependent upon a few 
relatively simple dominant factors. 
Self Red. There are two kinds of red, genetically distinct in their behavior 
toward self white. Possibly the factor or factors which affect, the white may 
be distinct from the factors for red. 
