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 
Sous Roan (7389) 
>< Lancaster 
@Champion Comet ce 
of England (11663) 
6 Bas (17526) x Virtue x Speer ait) 
ran uke erdan 
of Gloster Lord Raglan Crusade 7938 
19900 (26288) Rarer? of “ (13244) Brenda 
loster 9t 
Duchess of Lord Garlies 20236 
Gloster 6th (14819) 
Duchess of Gloster 
Royal Duke 
of Gloster x Lancaster { X Queen’s Roan (7389) 
20901 © Champion Comet 
(29864) of England (11663) 
' eal (17526) X Virtue ee se eeeae (11906) 
imulus an 
@Lord Raglan { x Crusade (7938) 
Mistletoe (13244) x Brenda 
Maidstone Matadore (11800) 
Phantassie 
Roan Al A2 A3 A4 A5B 
Gauntlet Will Honeycomb (5660) 
45276 The Queen’s 
(35284) (L Roan (7389) 
ancaster 
Comet ara | @ Will Honeycomb (5660) 
(11663) Lupin 
Champion of Plantagenet The Duke of Lancaster, 
England (11906) 10929 
(17526) Virtue Madaline 
Verdant { as Exchequer (9721) 
\ TIgg 
Princess 
Royal @Lord Raglan { X Crusade (7938) 
Thee (13244) \ x Brenda 
e Czar 
| (20947) Corianda { ene Baron (13833) 
zarina 
Carmine 
John Bull J Rumous (7456) 
(11618) \ Mayoress 
| Cressida 
Clipper { Billy (3151) 
Fic. 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 
Z = 100 (Pa+1 cae, Qn+1) 
eave 1 
which is essentially a mathematical expression of the relation in per 
cent. between the maximum number of different ancestors which an indi- 
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