176 



INBREEDING AND OUTBREEDING 



velop to twice the extent of either parent, because there 

 are present eighteen different factors instead of nine. 



TABLE VII 



COMPOSITION OF A MENDELIAN TRI-HYBRID IN F 2 WHERE THE DEVELOPMENT 

 WHICH EACH INDIVIDUAL ATTAINS DEPENDS UPON THE NUMBER OF 

 HETEROZYGOUS CHROMOSOMES CONTAINED AND THEREBY UPON THE 

 TOTAL NUMBER OF DIFFERENT FACTORS PRESENT. 



Distribution of the F 2 individuals according to the development attained 



Classes 6 8 10 12 =4 



Frequency 8 24 24 8 =64 



Number of classes 

 Total population 



Following this hypothetical case into the second gen- 

 eration by selfing or by interbreeding the individuals of 



