STI DIKS OX INBREEDING. VIL-SOME FUE^ 

 TIIHK ( ONSIDEBATIONS REGARDNG THE 

 MKASl'REMENT AND NUMEKICAL EX- 

 PKIISSIOX OF DEGREES OF KINSHIP^ 



DK. RAYMOND PEARL 



1. In this series of studies certain concepts regarding 

 tlie quantitative aspect of inbreeding have been pre- 

 sented. These concepts have in part been rigorously 

 defined, and expressed in mathematical form. It is de- 

 sirable to repeat here and extend in certain directions, 

 the definition of two of the most fundamental of these 

 concepts. 



I. Inbreeding is defined in these studies as the condi- 

 tion or state in wliicli an oi-ganism has in fact fewer dif- 

 ferent ancestors tlian the mnximnm number possible. 



The degree or anidinir dt' iiibiroding (total) is measured 

 by a series of iul>ft'< dnifi cirijicicnts, owe for each ances- 

 tral generation, dcfiiicd 1)> tlic rollowiiig eiiuatioii: 



where (U'liot.- tlic iiiaxiiiiiiin po^^hlc ininilxT of dif- 

 ferent iiidividiiai^ involved in llu' niatin.us cf the >/ -f 1 

 generation../ , t li.' /^^// nuniluM- of .li ff.'i-.Mit in<li vi(hials 

 involved in tlic^e niatinu>. and X„ is the inlirccdinij 

 coefficient for the ;/ Mli an.-e.Tral -enerat ion. 



11. A ^tate or <-ondition of n h,fioush,i^ or kinship he- 



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