Part 1

PIEBALD RATS AND SELECTION

AN EXPERIMENTAL TEST OF THE EFFECTIVENESS OF SELECTION AND OF THE THEORY OF GAMETIC PURITY IN MENDELIAN CROSSES

BY W. E. CASTLE AND JOHN C. PHILLIPS

WASHINGTON, D. C. PUBLISHED BY THE CARNEGIE INSTITUTION OF WASHINGTON 1914

CARNEGIE INSTITUTION OF WASHINGTON, PUBLICATION NO. 195

PAPER NO. 21 OF THE STATION FOR EXPERIMENTAL EVOLUTION AT COLD SPRING HARBOR, NEW YORK

FROM THE LABORATORY OF GENETICS OF THE BUSSEY INSTITUTION

Copies of this Book were first issued FEB 18 1914

PRESS OF GIBSON BROTHERS, INC. WASHINGTON, D. C.

CONTENTS.

Page.

Introduction 5

Material and methods 7

Plus selection series 9

Minus selection series 12

Return selection 13

Crosses with wild rats 16

Crosses with black “Irish” rats 18

Plus selection of “extracted hooded” rats 20

Crosses of the plus race with the minus race 22

Summary of results 22

Discussion 23

The “mutant” series 25

Bibliography 31

Tables 32-54

Explanation of plates 56

PIEBALD RATS AND SELECTION.

INTRODUCTION.