Dun Factor vs Countershading
My foal has stripes. Is it dun factor, or countershading?
Copyright and "Up to Date" Note:
Please note that all of the text information on this page was
originally composed by me unless otherwise referenced,
and was typed with great thought. I have read books and many educational
web sites to contribute to my knowledge base. Some of the content was
created in the late 1990's, and may need to be updated. With 300+ pages in this
web site, I can't remember which pages need updates all the time. If you see
an out-of-date page, let me know so I can update it.
Some photos were donated by
people that have horses with color examples needed to provide educational
content. For that reason, permission is not granted for anyone else to use
photos from these pages.
Please feel free to link to this page, but do not copy the
content and place it on your site.
"UP TO DATE" Note:
Some of the color/informational pages on my site have not been updated
for a long time due to my lack of free time to do so.
I am leaving the pages up because they are still helpful. BUT, some of
the terminology is incorrect and there is also NEW knowledge available
regarding color genetics. Some day, I will update these pages...when
time allows.
Click
here to learn
more.
|
"Countershading" is a form of striping that is probably a
remnant of primitive camouflage, but which is not the same as dun
striping. It is not a dilution, and is often only visible on young
horses.
Some horses will retain some countershading for their whole lives,
but it is far less distinct and contrasting with surrounding colors when
compared to dun factor striping...usually.
;-) 2016 update:
UC Davis has information about possible genetic causes of stripes that
are not dun factor. When you reach the bottom of this page, you'll get a
little more information and a link about this.
There is often a great difficulty determining a horse's
color when it comes to dilution genes, especially as foals. Because
of countershading, sooting, and other color modifications, foals are often
mislabeled as duns or grullas when they really should be registered as
buckskins or blacks. See the bottom of www.grullablue.com/grullocolor.htm
for photo examples of foal coat colors that can easily be mistaken for
dun/grullo colors.
As horses shed their foals coats, it should
become more readily apparent if they carry the dun factor trait or not.
Not always, but usually. Sometimes, a DNA test is the best action for an
overly-anxious owner to determine actual color. If one does not want to
spend the money to test, then time is often the answer...most
horses will show their "true color" by the time they shed off their winter
hair as a yearling.
The
following photos are of horses that are NOT dun-factored
horses.
Examples of Countershading (NON-dun factor striping) Markings
![](../images/thumbnails/countershading_small.jpg)
Not Dun Factor
This bay foal has a good example of a countershading
stripe. There are NO duns in his background, so we know he is
a bay with countershading. Most likely, his stripe will
disappear when he sheds off as a yearling. |
![](../images/thumbnails/2005/stripe12hours_small.jpg)
Not Dun Factor
A black foal with countershading-caused dorsal and shoulder barring.
Click here for proof that this filly
is not dun factored. |
![](../images/design/richdesign/hbar2.jpg) |
![tuscarorastablesdotcom.jpg (7392 bytes)](grullocolorpage/tuscarorastablesdotcom_small.jpg)
Not Dun Factor
A black foal with countershading.
|
Not Dun Factor
DNA tested buckskin with NO dun factor gene. |
![](../images/design/richdesign/hbar2.jpg) |
![](foalcolors/thumbnails/bay_countershading_stripe_small.jpg)
Not Dun Factor
This foal is bay or bay roan, but has an amazing countershading
stripe and shoulder patch that will disappear over time. He can not
be a dun, as he does not have dun factor genetics behind him in the
pedigree. |
![](foalcolors/sootybuckskin/huge_countershading_small.jpg)
Not Dun Factor
Super pictures of buckskin foals with countershading stripes that
are not caused by dun factor. Notice that the dorsal on these foals
stops abruptly at the top of the tail. The foals also do not have
ear tips. |
![](../images/design/richdesign/hbar2.jpg) |
![](foalcolors/smokyblack/black_foal_legs_small.jpg)
Neither dun factor nor countershading.
These are not stripes. This is a hair pattern that shows up best on
black and blue roan foals' back legs (and even hips), and that many people mistake for leg
bars. It is not, and is probably a trick of lights on waved/curly hair. |
![](foalcolors/smokyblack/black_foal_legs_small.jpg)
Not Dun Factor
Countershading stripes on black and smokey black foals' legs are
fairly common, but disappear over the first year. |
![](../images/design/richdesign/hbar2.jpg)
Show What You Know!
The pictures below show examples of horses that may or may not
have dun factor. Can you get the colors correct by looking at these
pictures?
|
Interesting picture, below. It shows how hard it
is to guess horse colors when you can't see "the whole picture"
through multiple photos, seeing the horse in person, and/or knowing
the sire/dam genetics.
Without looking anywhere else but at this photo,
what colors do you think these two yearlings (below) are?
![](grullocolorpage/dunfactors/yearling_backs_small.jpg)
Click the photo above to enlarge it.
Photo will open in a new window.
Then click
HERE
to see if you got it right! |
![](../images/thumbnails/colorpages/dun_countershaded_champagne_small.jpg)
Click the photo to view it full sized.
3 dun factors, one countershading (non-dun).
Can you tell which is NOT a dun factor dorsal stripe?
![](../images/thumbnails/colorpages/stripes_small.jpg)
2 dun factors and one non-dun striping. Which isn't a dun stripe?
Click here
for the answer. |
This mare has been DNA tested, and is BUCKSKIN, not dun
or dunskin.
Her test results concluded that she does NOT have a dun factor gene. Her
stripes are amazing, but are apparently caused by another factor (possibly
nd1).
Despite having a dorsal stripe with shading on the side, some leg stripes,
dark tips on the backs of the ears, and even faint cobwebbing on her
forehead, she is not a dun nor dunskin! Thank you for the great pictures,
Kirsty!
![](grullocolorpage/dunfactors/countershading/cobweb_kirsty_small.jpg)
UC Davis Information about Dun and Non-Dun Stripes
Three variants in DNA sequence explain phenotypes (how
horse "look" to the eye) related to Dun dilution:
-
D (presence of dun dilution
and primitive markings)
-
nd1 (not Dun-diluted;
primitive markings are present but expression is variable). Think of "nd"
meaning "not dun."
-
nd2 (1,617 bp deletion, not
Dun-diluted, primitive markings absent). Think of "nd" meaning
"not dun."
-
With respect to variant interactions, D is dominant
over nd1 and nd2; nd1 is dominant over nd2.
-
The VGL offers a DNA test that will provide
information for both dun dilution and the primitive markings.
Click here for more information.
This page last updated
08/10/20
If you notice this date being 2 years or older, please let
us know that we need to check out this page!
|