Knight — 166 — Dictionary 



gives the percentage of homozygous individuals, in any one genera- 

 tion, belonging to the backcross-parent (recurrent-parent) genotype 

 as regards the n genes under consideration. 



Inbreeding Coefficient. — Wright's coefficient of inbreeding is 

 a calculation of the average percentage of homozygosis to be ex- 

 pected from any particular system of mating. The formula is : 



F. = 5[(J)"+"'+'(l + Fo)\ 

 where, 



F^ is the inbreeding coefficient of the individual, 



F^ is the inbreeding coefficient of the common ancestor, 



n is the number of generations between the common ancestor 



and the sire, 

 n' is the number of generations between the common ancestor 



and the dam, 

 S represents summation. 



Mean-square Error: 



4 



'5(X - x)* 



n - 1 



where X is a single observation, x the mean of all observations, 

 S stands for summation of the series and n is the total number 

 of observations. 



Napierian Logarithms: 



To convert ordinary logarithms to Napierian, multiply by 2.30259 

 To convert Napierian logarithms to ordinary ones, multiply by 

 0.43429. 



Phenotypes. — The maximum number of distinct phenotypes which 

 can appear in Fi when complete dominance obtains is given by 

 calculating 2" where n is the number of factors involved. 



Progeny Size. — For an expected ratio of x:y the probability (P) 

 of the occurrence of at least one member of the y phenotype in a 

 progeny of n individuals is given by : 



P = 1 



(X -f 2/)- 



Progeny sizes for probability levels of 0.95, 0.99 and 0.999 are 

 given below for simple ratios : 



