A NOTE ON THE ORIGIN OF 
PIEBALD SPOTTING IN DOGS 
(C5 (C5 Wiassos 
Carnegie Institution of Washington, Cold Spring Harbor, N. Y. 
foxhounds, beagles, Boston terriers, 
St. Bernards, and collies, are char- 
acterized by the possession of a 
piebald coat pattern. In this pattern, 
large and relatively regular, and defi- 
nitely localized white spots occur on a 
colored ground. The extreme form of 
such spotting is seen in bull terriers. 
Here the entire skin and coat is com- 
monly unpigmented, the eyes alone 
being colored. The appearance of ex- 
ceptional individuals, however, in which 
small red or yellowish spots are found 
on the head, near the eyes or ears, 
shows that the pattern is really one of 
greatly reduced spotting and not of 
true albinism. 
On the other extreme of the spotted 
series one finds, among breeds normally 
solid colored, certain animals in which 
one or more of the feet may be white, or 
which may possess a white spot or blaze 
on the chest. Data on Great Danes, 
collected from the American Kennel 
Club Stud Books indicate that such 
spots are hereditary and are due to a 
factor which is hypostatic to solid 
colored coat. (Little and Jones,! 1919.) 
Such animals, which show a slight 
degree of white spotting, have, by some 
been considered as being forms from 
which, by rigid selection, spotted breeds 
have been developed. That this is also 
the case in rodents has been stated by 
Castle? (1916, page 125) as follows: 
UY . Rarely does it (the degree of 
spotting) go beyond these slight and 
inconspicuous markings. But under 
artificial selection in captivity it is 
possible rapidly to increase the extent 
of the white areas in the coat, which 
then takes on striking and often rather 
S texan varieties of dogs such as 
1 Little, C. C., and Jones, E. E., 
2 Castle, W. E., ‘‘Genetics and Eugenics.” 
12 
definite outlines, as in Dutch marked 
rabbits, English rabbits, hooded rats, 
and black-eyed white mice. ... The 
production of white-spotted races from 
small beginnings observed in wild stocks 
has been accomplished in the laboratory 
by Castle and Phillips in the case of 
Peromyscus, and by Little in the case 
of the house mouse (unpublished data).”’ 
Inasmuch as the inference from the 
above is that the writer, among others, 
has by selection developed from a wild 
race of rodents with a small amount of 
spotting, a race of heavily spotted 
animals, it should be stated that progress 
from the original degree of spotting 
observed, in the wild mouse used, was 
made only after a cross with a tame race 
and that following the cross progress was 
so rapid that the introduction of modifying 
factors by the unspotted race used un- 
doubtedly had occurred. 
EVIDENCE THAT SPOTTING IN DOGS MAY 
OCCUR BY MUTATION 
By this I do not mean to assert that 
some progress might not be made by 
selection alone within the race in which 
the spotting originated, but merely to 
point out that there is little or no ex- 
perimental evidence that the ‘ Dutch” 
or “English” rabbits or black-eyed 
white mice or hooded rats mentioned by 
Castle were developed by selection 
alone, within a wild race, showing a 
minute degree of spotting. It is pos- 
sible that this is the case, and will 
remain so until their origin de novo is 
demonstrated and analyzed; but in the 
meantime it is interesting to review two 
cases in dogs which give direct evidence 
as to the origin of spotted individuals 
and which suggest that a spotted race 
JourNAL oF HEREDITY, October, 1919, Vol. x, No. 7. 
Harvard University Press, Cambridge, Mass. 
