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Getting Informed…About
Dunalinos
www.enloequarterhorses.com
Visit Enloe
Quarter Horses/Horse Color Genetics Message Board to post color questions!
Ever
seen a horse that looks like a palomino, but has dun factor including a dorsal
stripe? If you
have, it was probably a "Dunalino".
These semi-rare horses are registered as red dun in the AQHA (American Quarter
Horse Association) and have been known to be called Red Dun, Red Dun with flaxen
mane and tail, Palomino Dun, and most commonly, Dunalino. The context or
this article should be taken in terms
of stock horses, specifically quarter horses. There are coat pattern genes
such as overo, tobiano and appaloosa that will vary the appearance of the color
further.
Genetics behind the color
Quick
genetics lesson - Genes are located on strands of DNA. Two alleles
meet at a specific point (called a locus) to form a gene. A foal receives an
allele for a gene from each parent. The two combine and you have a
gene. At this time, data on the horse has not been mapped for
all genes. Therefore, much of the data and analysis available is an
educated guess based on progeny tests rather than actual allele/gene
analysis. The following genetic description comes from the University of
California - Davis, a leader in equine genetic research.
Dunalinos
carry both the Creme and Dun genes. The Creme gene dilutes the body coat to a light shade of gold. It also
turns the mane and tail some shade of cream or white. On a sorrel or
chestnut horse, the Creme gene turns the horse palomino. On a bay, the
Creme gene turns the horse buckskin. The dunalino will carry only one
Creme gene and can not be homozygous for the Creme gene.
The Dun gene
normally dilutes a horse's body coat to a lighter color and adds several or all
the dun factors to the horse's body. The Dun gene changes a sorrel to red dun, a palomino to dunalino,
a black to grullo, and a bay or brown to dun. A dunalino may carry one or
two Dun genes.
The genetic mapping of a dunalino horse's color is believed by the University of
California-Davis to be
ee D? CcrC ??(unknown Agouti(A or a)) rr gg
where capital letters are dominant, small letters are recessive, and ? may be either dominant or recessive. Dominant alleles mask recessive alleles, meaning recessive alleles will only be displayed when they are in the homozygous form.
What are these genes?
E The red-factor gene. This gene makes the points (mane, tail, legs) black. Because Dunalinos have red or gold legs, we know they are "ee" and there is no need to test for red-factor.
D The dun factor gene. A horse can have up to 9 different dun factors, but they will always have at least a dorsal stripe. Other factors include zebra stripes on the front and/or back legs, a transverse stripe over the wither, neck barring (extra stripes/shadowing along the neck), mottling (dark speckles on the forearms and lower hind quarters), tipped ears (actual stripes on ears) and lined ears (black/dark brown along the edge of the ear), Frosting over the mane and tail, a face mask on the bridge of the nose, and cob webbing between the eyes. A dunalino may be Dd or DD. If a dunalino is DD, its offspring will all be dun factored, regardless of the other parent's color.
A This is the Agouti gene. These genes allow/disallow the horse to have a black body if it has at least one "E" gene. If a horse has a dominant agouti gene (A), it will allow the horse to only show black on the points and not the body (aside from dun factor). If no dominant agouti gene is present, the body may be black (Black, grullo, blue roan). Because these genes are displayed only when an dominant "E" is present, they do not affect the body color of a dunalino which is "ee". However, these genes will affect the dunalino's ability to produce black bodied foals. Because two recessive agouti genes (aa) are required to produce the black body color, a foal must inherit one from each parent. If the parent is "AA", it does not have a recessive agouti to pass to it's offspring and all offspring will be body colored in a shade of brown or cream.
C This is the Creme gene. The dominant form of the creme gene is Ccr and all true dunalinos buckskins and palominos have a dominant creme gene. A horse that is homozygous for the C gene (CcrCcr) is a cremello or perlino.
R This is the roan gene and its characteristics are only displayed in dominant form. A dunalino can have a dominant roan allele, but then, in the AQHA registry, it becomes a red roan and should be registered as one.
G This is the gray gene, and its characteristics are only displayed in dominant form. A gray can be a "base color" of dunalino, but then, in the AQHA registry, it is registered as gray.
The AQHA registers all dunalinos as red duns. There is no classification of "dunalino" but the AQHA will include "dorsal stripe" as a marking. Many people are tempted to register their dunalinos as palominos because of the visual characteristics, but problems arise if the offspring they produce is dun factored when bred to a non-dun factored horse because two non-dun factored horses may not produce dun factored offspring. Technically, a dunalino can carry two copies of the dominant dun factor gene and only one of the creme gene, making it possible for a dunalino to be more "dun" than "palomino". Of course most dunalinos carry just one copy of the dominant dun and creme genes.
Dunalinos are good dilute color producers. 75% of the offspring will be either dun factored, creme diluted, or both. Because of this, they are highly prized as breeding animals.
To produce a dunalino, one parent must carry a
creme gene (buckskin, palomino, smoky black, dunalino) and one parent must carry
a dun gene (dunalino, red dun, dun, or grulla). All dun factored horses
show their dilution. Some creme carriers may be hard to identify such as
those that carry a dun gene and have black points, like the dun and grulla.
Unfavorable colors may occur if two creme carriers are bred together. The
result may be a cremello or perlino, neither of which was registerable in the
AQHA until 2003. After AQHA voted to accept perlinos and cremellos into
its registry, the colors have gained some acceptance, but are still generally
thought of as undesirable by most horse breeders.
Additional web sites with genetics information:
Dunalino Pictures: The Corner Corral located in Amasa, Michigan http://groups.msn.com/thecornercorral
The genetics behind the hide: http://www.geocities.com/Baja/Outback/2936/
University of California-Davis: http://www.vgl.ucdavis.edu/~lvmillon/
Copyright © 2002, 2003
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