This is a fascinating subject. I would like to recommend a book on Colour Genetics called "Horse Colour Explained" by Jeanette Gower. Her website is on our links page.
Having a read of the following few paragraphs will hopefully simplify the genetic maze and help clarify any questions you may have.
A Little On Colour
Every horse has two locations in its genetic code where a colour modification gene can exist. These genes are commonly called "crème genes". They make the horse's base colour one or two shades lighter, depending on whether there are one or two of them present.
Horses like sorrels/chestnuts, bays, and blacks have no crème genes. These are the base or basic colours. Some horses like palominos, buckskins, and smoky blacks have one crème gene. They are called "single dilutes". Other horses like cremellos, perlinos, and smoky crèmes have 2 crème genes. These are called "double dilutes".
If you breed a bay or chestnut horse to a single crème dilute, such as a palomino, buckskin, or smoky black, you have a 50% chance of producing a palomino, buckskin, or smoky black foal.
One single crème gene only affects the red color in a horse's base coat. It does not dilute the black colouring. Therefore, a chestnut based foal with one crème gene becomes a palomino, a bay based foal plus one crème gene becomes a buckskin (the red body coat of a bay is diluted to gold while the black points remain black), and a black based foal with one crème gene becomes a smoky black. Palominos, buckskins, and smoky blacks are single crème dilutes.
Perlinos, cremellos, and smoky crèmes are the result of breeding two horses who each have at least one crème gene, like buckskin to palomino, palomino to cremello, palomino to palomino, etc. They are double crème dilutes, having received one crème gene from each parent. Double dilutes have two crème dilute genes and will pass one crème gene to their foals 100% of the time, diluting a bay to buckskin, a chestnut to palomino, and a black to a smoky black (remember the single crème gene doesn't affect the black colour so smoky black will produce approximately 50% golden foals themselves). Palominos, buckskins, or smoky blacks bred to a double dilute, have a 50% chance of producing a palomino, buckskin, or smoky black foal and a 50% chance of producing a perlino, cremello, or smoky cream foal.
Double dilute bred to a double dilute will always produce a double dilute perlino, cremello, or smoky cream. A perlino is a bay based horse with two dilute genes, a cremello is a chestnut horse with two crème genes, and a smoky crème is a black based horse with two crème genes. While the single crème gene does not affect the black colour, a double dose of the gene does by diluting the black points of a perlino to a cinnamon colour. The mane and tail of a cremello will be white or ivory. Perlinos, cremellos, and smoky creams range from nearly white to shades of ivory. They also have beautiful ice blue eyes and pink skin.
Double dilutes are not freaks of nature. They are not weak or inferior horses. They will not produce lethal white offspring and they are no more prone to diseases or conditions than our traditional colours are. The crème gene makes the horse's colour lighter but does not remove it, even when there are two present. They can not make a horse an albino. Albinism is created when an offspring receives two recessive genes from its parents. The crème gene, which causes a cremello, is not a recessive gene. The crème gene affects the colour of the horse's hair, skin, and eyes. Nothing else. It is the same horse with or without the crème genes, only the colour is different. Dilutes have the same immune system, bone density, resistance to sunburn, stamina, and every other strength it would have as a red, bay, or black. |
 |
