CONTENTS 
A case of partial linkage in maize. : 
Chromosome interpretation of linkage. 
Linkage in Drosophila. 
The factor groups : 
An illustrative case from the Arse group 
Linkage in the second and third groups . 
Linear arrangement of factors 
Application in Drosophila . 
The mode of inheritance in crossing-over ; 
Experimental verification of theory of linear arr: marement oe cree 
Interference . ; : 
Linkage phenomena in oinen a ae Sails anime alg : 
Mathematical relations in linkage of phenomena . 
CHAPTER VII 
Tue Nature aNd Expression or MENDELIAN Factors 
Introductory . : : 
Conception of Eee as eee in Silianeeme 
Factors the genetic representatives of characters . 
Manifold effects of factors . : 
The variability of factor expressions 
Duplicate factors . 
Multiple factors 
CHAPTER VIII 
ALLELOMORrHIC RELATIONSHIPS IN MrNDELISM 
Introductory. f 
Character Pec one Noe in Pisuna : 
Dominance defined . 
The extent of dominance ; 
Intermediate expression in the hy Bele 
Variable character expression in the hybrid . 
Competitive action of factors 
Mosaic expression of a character . 
The presence and absence hypothesis . 
Multiple allelomorphism . 
In Drosophila . 
In other species 
Arguments in favor of the ronoption of Sanaa eiletomenaln ent 3 
CHAPTER IX 
Types or Factor INTERACTIONS 
Introductory . 
Aleurone color factors in maize. 
Comb characters in fowl. 
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