598 



GENETICS IN RELATION TO AGRICULTURE 



for the breeder to suspect that something has been lost in that line of 

 descent, something that a pedigree, however excellent in remote ancestors, 

 cannot supply. 



The Coefficient of Inbreeding. We would call attention to Pearl's 

 coefficient of inbreeding as an instance of another refinement which has 

 been advocated for use in practical breeding operations. Pearl proposes 



X Queen's Roan (7389) 



FIG. 232. Pedigree of Roan Gauntlet, a famous Cruickshank Shorthorn bull. 



that inbreeding be used in a generic sense to include all cases in which 

 some of the matings in the pedigree were of related individuals. In 

 order to indicate degree of inbreeding he suggests the use of a coefficient 

 of inbreeding of the form 



_ 100(P+l-Qn+l) 



6n 



Pn 



+ 1 



which is essentially a mathematical expression of the relation in per 

 cent, between the maximum number of different ancestors which an indi- 



