THE SELECTION PROBLEM IN ANIMAL BREEDING 501 
his herd, no other animals were introduced from outside sources. Of 
necessity, therefore, his was a method of close inbreeding, and he did 
not shrink for a moment from using this method to the fullest extent. 
The same method of breeding characterizes the work of other early 
breeders. Thus one of the most famous of early Shorthorn bulls, Comet 
(155) was very closely inbred as shown by the pedigree in Fig. 194. 
At public auction this great bull was sold in 1810 for 1000 guineas, 
a very high price at that time. He was considered the crowning achieve- 
[ Foljambe (263) 
Bolingbroke (86) ; 
| Young Strawberry 
Favorite (252) 
| Foljambe (263) 
Phoenix | 
Favorite 
| Foljambe (263) 
‘ Bolingbroke (86) 
eau) lPvoune Strawberry 
Favorite (252) 4 
Foljambe 
Phoenix | 
Favorite 
Young 
Phoenix 
[eptiarale (263) 
Phoenix 
| Young Strawberry 
Fig. 194.—The pedigree of Comet (155), an illustration of extreme inbreeding in Shorthorn 
foundation stock. 
ment of Charles Colling’s notable career as a breeder of Shorthorn cattle. 
The extremely close breeding shown in this sample pedigree from a 
notable herd of Shorthorn cattle may again be used as an argument in 
support of the isolation interpretation of selection in successful practical 
breeding operations. 
In fact throughout the entire history of animal breeding, improve- 
ment has been most strikingly referable to the influence of a limited 
number of families and individuals of superior excellence, a fact which 
speaks strongly for the isolation view of selection. Every breed has its 
famous animals and families, and every breeder who has studied pedigrees 
at all must have been impressed by the small percentage of early animals 
which are represented in almost every pedigree of present-day individuals 
of the breed. The ‘“‘search for the prepotent sire” and full utilization 
of him when discovered have been the central features of the breeding 
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