Simpson: Coat-Pattern in Mammals 



THE BREEDER'S TEST FOR PURE PEDIGREE 



A yearling sow, out of a tested Belted Red sow. and a supposedly pure Tamworth sire. Con- 

 trary to expectation, she has an all-white hind leg. wSuch a trait does not belong to either 

 of her parents; Mr. Simpson is convinced that it shows a Berkshire taint in her supposedly 

 pure Tamworth sire. (Fig. 2.) 



pending on two colors, the width of 

 white belt in Hampshire and its hybrids, 

 or synthetic belts, varies in dimension 

 from the entire pig white except head 

 and rump, to all black except a narrow 

 white line, or only the front feet white. 

 With the Hampshire of pure pedigree 

 there are a few all-whites and some all- 

 blacks. The factor for making white 

 in the belt and the factor for self- 

 ing the anterior-posterior coat seem to 

 be always in contest for supremacy : and 

 both must be in happy equilibrium to 

 produce the standard pattern. I have 

 made apparent proof that either of 

 these factors may be strengthened 

 against the other by the conscious addi- 

 tion of other factors that work to the 

 help of one of them. And illustrating: 

 — Some red sows were selected that were 

 the second Duroc top on Poland-China : 

 out of a numerous bunch two sows were 

 found free from white-spots or markings 

 that indicate a hyperpotent red drown- 

 ing the latent spotting of the Duroc and 



the white-spotting factor of the Poland- 

 China. These all-red sows were bred 

 to pure Hampshire, that normally 

 should sire 100% belts: but the result 

 of their 21 pigs was 11 self blacks and 10 

 belted of various but very narrow 

 width, the ends of good Hampshire 

 black. From other hybridizing with 

 the same boar I believe that had we 

 selected from the same broods as these 

 hyperpotent red sows some others show- 

 ing spots of white we wotild have gotten 

 near 100% of Belts. We may say that 

 both factors for belting pattern are 

 Mendelian, but must provide that no 

 other element interferes. 



Belted pigs are occasionally met 

 among several crosses free from Hamp- 

 shire, Yorkshire or Tamworth blood. 

 My recollection from childhood days, 

 when my father was improving the 

 native black hog of Illinois with a mostly 

 white hog from Ohio, is that there was 

 about 5% of belted pigs that were called 

 by the settlers "listed-hogs." And in 



