114 PHYSIOLOGICAL GENETICS 



internal, genetic, controlling these different conditions may act 



upon dominance. But no actual work on the chemistry of 

 heterozygotes has been done. 



There arc also some data from Scott- Moncrieff's work on 

 anthocyanins which arc relevant. Though this author is not 

 inclined to lay down definite rules in regard to dominance, 

 she points out some uniformity in behavior: plastid pigment, 

 copigment, anthoxanthin, and anthocyanin are dominant to 

 their absence. More oxidized and more methylated pigment 

 is dominant over less oxidized or methylated. Diglycosidic 

 and acylated anthocyanins are dominant over monoglycosidic 

 and normal anthocyanin. More acid sap is dominant over less 

 acid. It is obvious that such results may be interpreted in a 

 general way in terms of reaction velocity, the phenomenon that 

 we have always found in some way underlying the phenomena 

 of dominance. 



E. Dominance in Multiple Allelomorphic Series 



A considerable body of facts regarding dominance have been 

 derived from the study of multiple allelomorphic series, and 

 some of them have already been reported. A number of authors 

 have realized that such facts may have an important bearing 

 upon the understanding of gene action, viz., Goldschmidt, 1917- 

 1927; Zeleny, 1920; Wright, 1925; Hersh, 1930a; Dobzhansky, 

 1930; Muller, 1932a; and Goldschmidt, 1937. The pertinent 

 facts up to 1930 have been brought together and analyzed 

 critically in Stern's monograph (1930). We shall recount first 

 the types of facts, closely following the grouping employed by 

 Stern, as well as his examples, and then try to analyze them. 



There is first the group of multiple alleles with a simple quanti- 

 tative sedation of the effects, not considering now the cases of 

 pleiotropic action of the same genes. Here the following types 

 of behavior in regard to dominance are found: 



1. Each higher allele is dominant over the lower one. Exam- 

 ple: flower color of Lathyrus: RE self-colored dominant over 

 rV; spotted, over rr white. 



2. All alleles are intermediate in the compound. Example: 

 the series of genes for eye-form Lobe in Drosophila +, L, L 3 , L 2 ; 

 the pigment series of Lymantria caterpillars. 



