MENDELISM 



b. Dominance. In every individual there are two 

 determiners for every unit character, one derived from 

 each parent. If this pair is different, i. <?., if the zygote 

 is a heterozygote, one dominates the other and deter- 

 mines the apparent character of the organism. 



The alternative recessive characters, although they 

 may be present in the germplasm, are unable to be- 

 come manifest in the somatoplasm so long as the domi- 

 nant characters are present. When, however, the domi- 

 nant determiner is absent, and the recessive is dupli- 

 cated, the recessive character becomes manifest. 



c. Segregation. The determiners of unit characters, 

 although they may be intimately associated together in 

 the individual, during the complicated process of ma- 

 turation that always precedes the formation of a new 

 individual, separate or segregate out as if independent 

 of each other and thus are enabled to unite into new 

 combinations. 



13. THE PRACTICAL APPLICATION 



Although the ratios for more than a trihybrid were 

 computed by Mendel, the experimental test was not 

 carried out by him, since it involves such large and com- 

 plicated proportions. 



In the case of four differing unit characters in the 

 parental generation, the offspring of the quadruple 

 hybrids derived from such an ancestry would include 

 256 or (3+1) 4 possibilities instead of 64 or (3+1) 3 , 

 as in the case of trihybrids. When ten differing char- 

 acters are combined in the parental generation, 



