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Contents

Preface to the Fourth Edition xi

1 Introduction 1 1.1 Basic Horse Color Identification 3 1.2 Basic Principles of Genetics, Genomics, and Molecular Biology 10 1.3 Pigment Cell Function and Genetic Control 18

2 Basic Dark Horse Colors: Bay, Chestnut, Black, and Brown 23 2.1 Bay, Chestnut, and Black 23 2.1.1 Definition and Classification 23 2.1.2 Genetic Control 26 2.2 Two Subtypes of Bay: Wild Bay and Bay 32 2.3 Seal Brown 34 2.4 Dominant Black 36

3 Modifications Affecting Most Colors 39 3.1 Shade 39 3.1.1 Definition and Classification 39 3.1.2 Genetic Control 44 3.2 Sooty 46 3.2.1 Definition and Classification 46 3.2.2 Genetic Control 50 3.3 Mealy 53 3.3.1 DefinitionCOPYRIGHTED and Classification 53 MATERIAL 3.3.2 Genetic Control 57 3.4 Mane and Tail Color on Chestnut and Sorrel 57 3.4.1 Definition and Classification 57 3.4.2 Genetic Control 61 3.5 Bend Or Spots 62 3.6 Dapples 63 3.7 Brindle and Chimeras 63 3.8 Eye Color 68 3.9 Foal Color 71 viii Contents

4 Dilutions of the Basic Dark Colors 75 4.1 Linebacked Dun 76 4.1.1 Definition and Classification 76 4.1.2 Genetic Control 90 4.2 Cream-related and Pearl Colors 93 4.2.1 Definition and Classification 93 4.2.2 Genetic Control 102 4.3 Champagne 107 4.3.1 Definition and Classification 107 4.3.2 Genetic Control 111 4.4 Silver Dapple 114 4.4.1 Definition and Classification 114 4.4.2 Genetic Control 120 4.5 Mushroom: Definition, Classification, and Genetic Control 122 4.6 Lavender 123 4.7 Other Dilutions 124 4.8 Compound Dilute Colors 125

5 Overview of the Genetic Control of Horse Color 131

6 Patterns with Individually Distributed White Hairs 137 6.1 General Considerations 137 6.2 Patterns of White with Individually Distributed White Hairs: Grey and Roan 138 6.2.1 Definition and Classification 139 6.2.2 Grey: Genetic Control 147 6.2.3 Classic Roan 148 6.2.3.1 Definition and Classification 148 6.2.3.2 Genetic Control 154 6.2.4 Frosty 156 6.2.5 White Ticking 157 6.2.6 Patterns of White Striping 159 6.2.7 Roaned 160 6.2.8 Other Roan Patterns 160 6.2.9 White Lacing 162 6.2.10 Birdcatcher Spots 163

7 Nonsymmetric Patches of White: White Marks, Paints, and Pintos 165 7.1 Face and Leg Markings 166 7.1.1 Definition and Classification 166 7.1.2 Genetic Control 169 7.2 Nonsymmetric White Body Patches: Paint or Pinto Patterns 170 7.2.1 Tobiano 173 7.2.1.1 Definition and Classification 173 7.2.1.2 Genetic Control 177 7.2.2 Calico Tobiano 178 7.2.3 Overo 180 Contents ix

7.2.3.1 Frame 181 7.2.3.1.1 Definition and Classification 181 7.2.3.1.2 Genetic Control 182 7.2.3.2 Sabino and White 185 7.2.3.2.1 Definition and Classification 185 7.2.3.2.2 Genetic Control 191 7.2.3.3 Splashed White 197 7.2.3.3.1 Definition and Classification 197 7.2.3.3.2 Genetic Control 198 7.2.3.4 Manchado 202 7.2.3.5 Overo Crop-Out Horses 202 7.2.4 Combination Paint Patterns 205 7.2.5 Paint Summary 209

8 Patterns with Symmetric White Patches: The Leopard Complex 211 Rebecca Bellone, Sheila Archer, and D. Phillip Sponenberg 8.1 Leopard Complex 211 8.1.1 Definition and Classification 211 8.1.2 Genetic Control 229 8.1.2.1 The Leopard Complex Allele 229 8.1.2.2 Modifiers Affecting Extent of White Pattern at Birth 231 8.1.2.2.1 Pattern 1: A Major Modifier Locus 231 8.1.2.2.2 Other Modifying Influences on White Pattern 233 8.1.2.3 Modifiers Affecting Leopard Spots 235 8.1.2.4 Modifiers Affecting Varnish Roaning 236 8.1.2.5 General Observations on Leopard Complex Pattern Expression 237

9 Overview of Patterns Adding White 239

10 Horse Color and Horse Breeding 243

11 Peculiarities of Hair Growth 247

12 Donkey Color 251 12.1 Colors of Donkeys 251 12.2 Patterns of White 261 12.3 Genetics of Donkey Color and Patterns 272 12.4 Summary of Donkey Color and Patterns 277 12.5 Hair Growth in Donkeys 278

13 Summary Tables 279

Bibliography 323 Index 335