No. 540] 



INHERITANCE OF COLOR IN CATTLE 



735 



have had three sources — an Anglo-Saxon red, the red of the Dutch 

 flecking, and the supposed Celtic red. The white may have come 

 through the Romano-British, through the Anglo-Saxon white or pos- 

 sibly through the white in the Dutch. The particolors and the roans 

 are of equally doubtful origin, although it probably is safe to assert 

 that they are due to the broods of latest importation; and it thus 

 seems fairly impossible to determine a priori how many distinct red, 

 roan, particolor or white types may really exist in the case of the 

 Shorthorn. The importance of this statement for any Mendelian in- 

 terpretation must be obvious. We may have rods which are domi- 

 nant, recessive or even heterozygous to white or even to other reds, 



We have seen that there is historically a possibility of two strains of 

 red and two strains of white having been mingled in the Shorthorn. 

 Determinants representing particolor and white markings can un- 

 doubtedly be introduced also; we confess to having made an attempt 

 from this standpoint which shattered with further examination of 

 Table I— but the ^ intn.ductimi needs a wider praet ise^ than Ave can 



vinced than we are at present of the soundness of such formulae we 

 should prefer to leave the invention to those who have had it. Coates 

 Herd Book presents a wide ramm of material and whatever we may 

 think of the categories selected, the record has been made by persons 

 in absolute ignorance of recent controversies about heredity. It is 

 therefore really impartial material for Mendelians to unravel. . . . 

 It would thus seem that no simple Mendelian formula can possibly fit 

 the Shorthorn cases. Koughly. such a formula approaches the data in 



theory of Mendelism being due to the purity of gametes. It is of 



The whole color problem in Shorthorns is a compli- 

 cated study in mongrelism and no single simple four-part 

 Mendelian ratio can be expected to explain it. Instead 

 of a single unit or a single uniformly dominant or reces- 

 sive series, there are two genetically independent unit- 

 behaving groups of units — one dominant, the other reces- 

 sive in their companion, i. e., their white phases. How- 

 ever, such companion traits— if the somatic blend is con- 

 sidered as simplex — when undistinguished, will give the 



8 Ibid., p. 444. 



