Morgan Horse Chestnut/Flaxen Color Research Project
by Sonya Sokolow

Preface

    I stood up to ask a question at Dr. Cecilia Pinedo's lecture on Dunn Horse Color at UC Davis Horse Day Symposium in 2001. I asked whether there are any known genetic markers for the popular color combination called "liver/flaxen" in the Morgan breed.  Professor  Pinedo answered that if I can identify a population of registered Morgans who are this color,  her Veterinary Genetics Lab at UC Davis may be able to answer the question.  Thus was born this project!  Many "thank you's" are due to the Morgan owners who eagerly supplied us with the photos and supporting data we needed for all the horses used in this study, as well as those horses submitted, but not used for various reasons. This study could not have been done without the information highway (Internet) which is now available to most of the Morgan owners who participated. Much appreciation also has to be acknowledged to all the UC Davis staff who squeezed the needs of this study into their already over-worked schedules.  Last but not least, THANK YOU to my husband (Stanley Sokolow) who helped me "push the buttons" on my computer and who wrote custom software in order to  expedite this study's  methods and procedures described below.

The Project

    The goal of the project is to discover the way that the flaxen color trait in Morgan chestnut horses are inherited.   To provide objective data, we are accumulating photos of registered Morgans with chestnut body color, both with and without the flaxen trait in their manes or tails.   We also are collecting photos of their ancestors and offspring.  Since the DNA for all Morgans registered since the 1980's is stored at the University of California in Davis, the photos and DNA can be used together to research this matter.   To obtain the photos, we have been obtaining the cooperation of Morgan owners, who have sent us photos and who are now adding descriptive information about these horses.   If you wish to participate, contact sonya@thesokolows.com .   We have written an article which hopefully will be published in a popular equine magazine or journal, as a general introduction to the topic and project.    A link to the article is in a box below.

Photo Albums

    The photos of horses in the study are being collected in albums on the web service called Flickr located at www.flickr.com.   They are available for viewing only by invitation.   If you would like to participate and view the horses, or add your own horses to the project, contact sonya@thesokolows.com .   Instructions and frequently-asked questions (FAQ) are on the links below.

The Pedigrees

    To visualize the relationships and images of the horses, we create enhanced pedigree drawings using our custom software.   The pedigrees are stored in web pages which require standard features (xhtml and standard vector graphics) that Microsoft Internet Explorer does not yet provide, but which the Firefox browser understands.  We recommend that you view the pedigrees with Firefox, which you can download and easily install for free from this web site:  Firefox .   Firefox also provides the ability to zoom in and out to better view small or large drawings.

    The pedigrees are available to view from this clickable index of the files:  Index of Pedigrees .   Here is an annotated example of a pedigree, with explanation of the symbols.   Male horses are represented by rectanges.   Females are ovals.   Flaxen chestnut horses are yellow.  Nonflaxen chestnut are orange.   Other body colors and chestnuts whose flaxen trait is still unknown to us are not colored.

The Mating Node Graphs

    To visualize the relationships among all of the horses in one drawing, we create a mating node graph.   You can find several versions of it in the Index of Pedigrees.    Here is one of them:  Small Mating Node Graph .   You will need the Firefox browser version 3 or later to view it, since earlier versions of Firefox and  Microsoft Internet Explorer do not understand standard vector graphics.   Firefox will let you zoom in and out to see detail or an overview.  An alternative is this version which may be viewable in your current browser but which does not zoom without loss of sharpness:  Small Mating Node Graph in png format .    Here is an explanation of the mating node symbols:  Legend of Mating Node Graph

Articles

"Breeding for Color"Article
Flaxen Color Genetic Research in Progress published in The Horse online.
Coat Color Studies Aid Health Research, Breeding Choices published in The Horse online.
Third Article in The Horse magazine online.  (Deals with methods and materials of the study.)

Small Mating Node Graph Index of Pedigrees Flickr Instructions
 Flickr FAQ
 Color Palettes
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