CONTENTS 
CHAPTER I 
MENDELIAN INHERITANCE AND THE CHROMOSOMES 
PAGE 
Introduction. The Groups of Linked Factors and the Chromo- 
somes a eee s £ a BBs caae 1 
The Inheritance of One Pair of Factors. . ........ 8 
The Inheritance of Two or more Pairs of Factors ...... 20 
CHAPTER II 
TYPES OF MENDELIAN HEREDITY 
Dominance and Recessiveness. . . eo oay ae a ae a Oe eae 27 
Manifold Effects of Single Factors... .......4.- 32 
Similar Effects Produced by Different Factors. ...... 36 
Modification of the Effects of Factors Busine Hts ine Bi Met lien Be,  GPIG 38 
I, By Environmental Influences , scat dag iah | Syrah se 38 
II. By Developmental Influences. . . .. 1... ee 42 
1II. By the Influence of Other Factors... .... 2s. 45 
IV. Conclusion . . oi Hee ado A a Bee 46 
CHAPTER III 
LINKAGE 
Examples Illustrating “Coupling”. . . © 2. 6 6 ee ee eee 48 
Examples Illustrating “‘Repulsion” ... 1... +e ee ee 51 
Examples of Different Frequencies of Crossing Over. ...... 52 
The Mechanism of Crossing Over... .- - 0 6 ee ee eee 59 
Double Crossing Over . ‘ & alitestighas  chysayeta cet le 62 
The Principle of Interference. «© - - eee ee ee es 64 
The Linear Arrangement of Factors shown by Linkage Relations . 64 
Linkage in Other Animals and in Plants... 1... se eee 70 
The Reduplication Hypothesis .......+.-. ic a aw a we TE 
