Table of Contents 



Preface \^ ^ ^^ iii 



1865 • Gregor Mendel 



Experiments in Plant Hybridization 1 



1903 • W. JOHANNSEN 



Heredity in Populations and Pure Lines 20 



1903 • Walter S. Sutton 



The Chromosomes in Heredity 27 



1905-1908 • W. Bateson and R. C. Punnett 



Experimental Studies in the Physiology of Heredity 42 

 Poultry, 44. Sweet Peas, 54. 



1908 • G. H. Hardy 



Mendelian Proportions in a Mixed Population 60 



1910 • T. H. Morgan 



Sex Limited Inheritance in Drosophila 63 



1913 • A. H. Sturtevant 



The Linear iVrrangement of Six Sex-linked Factors 



in Drosophila, as Shown by their Mode of Association 67 



1917 • Sewall Wright 



Color Inheritance in Mammals 78 



1921 • L. C. Dunn 



Unit Character Variation in Rodents 92 



1922 • H. J. MuLLER 



Variation Due to Change in the Individual Gene 104 



1925 • Calvin B. Bridges 



Sex in Relation to Chromosomes and Genes 117 



1925 • A. H. Sturtevant 



The Effects of Unequal Crossing Over at the Bar Locus 



in Drosophila 124 



1927 • H. J. MuLLER 



Artificial Transmutation of the Gene 149 



V 



