By Ann Streett-Joslin
The Cream (Cr) gene in horses is responsible for several common coat colors. It is one of five dilution genes or genes that “dilute” the base color of a horse. In an earlier article we looked at the Extension gene (Z) and the Agouti gene (A), which combine to create the basic horse colors of black, bay, and sorrel or chestnut. All horses have these genes in some combination, so regardless of whatever additional color modifier genes may be present, underneath there is a black, bay, or sorrel/chestnut coloration.
The action of the Cream gene is complex. The dominant characteristic of the gene is shown as Cr and means no dilution is allowed. The recessive version, cr, allows dilution or fading of the basic color of the horse’s hair in some way. Red pigment is diluted to yellow or tan while there is little effect on black hair.
The Cream gene is also an “incomplete dominant” gene. This means that if only one allele of the gene pair is present in the cr or recessive state, there is one kind of effect. If both alleles of the gene pair are cr, there is another effect. This table shows the results:
Both single and double dilution horsesone copy of the cream gene or twocan appear as many shades of yellow or cream. The color may change with the seasons or sun exposure. It may appear completely white. The only way to be sure is a DNA test.
A possible misconception with the cream gene is that if, for example, you breed a palomino to a palomino, you should get a palomino. Here’s what really happens:
By now, you may be thoroughly confused. This is a complicated gene and may be influenced by other genes when present, too. Remember to always look for what the base color may be and then consider the effects of this Cream dilution gene.
Palomino to Palomino = 50% Palomino
About the Author: Ann has been active with horses and the horse industry for over 50 years. From the show-ring, to state 4-H horse awards, to guest ranches, to driving and training youngsters, Ann is well-versed in the business. She is a CHA Master Level Riding Instructor and a CHA Clinic Instructor for English, Western, Equine Facilities Management, and Instructor of Riders with Disabilities. Ann is also a CHA Site Visitor, a therapeutic riding instructor and a Richard Shrake Resistance Free Instructor and Trainer since 1997.