Feb. 17,1923 
Inheritance in Swine 
565 
COLOR DATA FROM THIS INVESTIGATION 
WILD BY TAMWORTH CROSS 
The color of the Tamworth is a uniform cherry red which varies 
somewhat in intensity within the breed but not so widely as the red of 
the other common red breed, the Duroc-Jersey. The color of the wild 
hog has already been described. All of tie 38 Fj pigs produced in this 
experiment were born with distinct longitudinal stripes about 1 cm. in 
width, composed alternately of rather light red hairs and very dark 
brown hairs. These stripes extended all over the backs and sides, but 
the bellies were a uniform light red (PI. 1, B). Such variation as may 
have existed among the Fj individuals in the regularity of striping or 
in the contrast between light and dark stripes was too slight to admit 
of description or of measurement. 
All four F 2 pigs were striped in the same way except that the stripes 
were not quite so regularly continuous throughout the entire length of 
the pigs’ bodies as was the case with the F/s. These four pigs showed, 
however, three different belly colors, as follows: One with a uniform 
grayish white belly on which the hairs were apparently white, two with 
uniform, light reddish bellies like the F x s and one with a similar light 
reddish belly on which were scattered some large black spots both in 
hair and skin. 
The back-cross litter resulting from mating a Tamworth sow and an 
Fj boar included five striped and three nonstriped pigs. Of the five 
striped ones, two were like the F/s and three were faintly striped but 
possessed small black spots on their bodies. Of the nonstriped pigs, one 
was self red and the other two were red with small black spots. 
Obviously this suggests single independent factors for black spotting 
and for the striping pattern. It also suggests that the black spotting 
factor may diminish the intensity of the striping pattern, because all 
three of the back-cross pigs which were faintly striped possessed black 
spots. Since none of these pigs matured, it was impossible to apply 
the breeding test to this latter idea, but the existence of an F 2 pig which 
was both intensely striped and possessed black spots makes it seem more 
probably that the association of faintness of striping and black spotting 
in the back-cross litter was due either to chance or to linkage. The 
factors for striping pattern and for intensity of that pattern must both 
come from the wild hog, while the factor for black spotting probably 
comes from the Tamworth, since if it comes from the wild hog the latter 
must also possess an inhibiting factor which prevents the spots from 
showing in either the F 1 or the pure wild. The occurrence of the gray- 
bellied pig in the F 2 generation and the absence of this type from the 
back-cross litter suggests that the Tamworth may possess a partially 
dominant factor for deep red and the F 2 pig may be explained as the 
segregation of the homozygous recessive to that factor. This last sug¬ 
gestion is supported by the fact that the wild X Berkshire F t pigs, to 
be discussed later, showed this lighter color and by the fact that the 
adult wild X Tamworth F^s were a more reddish and less slaty color 
than the pure wild boars. This is the only actual evidence secured 
supporting this interpretation. No evidence was secured as to why the 
pure-bred Tamworth, which evidently carries a fundamental factor for 
black spotting, is prevented from showing that black in its own body. 
