>Grey is not necessarily dominant
Absolutly wrong. Grey is a clear somatic dominant gene. Check out the UC
Davis horse color genetics pages for more details.
<http://www.vgl.ucdavis.edu/~lvmillon/coatclr.html>
OK here is the info from that page. If you use their choice of letters to
distinguish the alleles it makes it easier, that's the set used by most
researchers and the easiest way to discuss color genetics with others.
There are several different loci that determine horse coat color.
TABLE 2
Alleles and Actions of Horse Coat Color Genes
Gene
Alleles
Observed Effect of Alleles in Homozygous and
Heterozygous Condition
W
W
w
WW: Lethal
Ww: Horse typically lacks pigment in skin, hair and
eyes and appears
to be white.
ww: Horse is fully pigmented.
G
G
g
GG: Horse shows progressive slivering with age to
white or
flea-bitten, but is born any non-gray color. Pigment
is always present
in skin and eyes at all stages of silvering.
Gg: Same as GG.
gg: Horse does not show progressive silvering with
age.
E
E
e
EE: Horse has ability to form black pigment in skin
and hair. Black
pigment in hair may be either in a points pattern or
distributed overall.
Ee: Same as EE.
ee: Horse has black pigment in skin, but hair pigment
appears red.
A
A
a
AA: If horse has black hair (E), then that black hair
is in points
pattern. A has no effect on red (ee) pigment.
Aa: Same as AA.
aa: If horse has black hair (E), then that black hair
is uniformly
distributed over body and points. A has no effect on
red (ee) pigment.
C
C
Ccr
CC: Horse is fully pigmented.
CCcr: Red pigment is diluted to yellow; black pigment
is unaffected.
CcrCcr: Both red and black pigments are diluted to
pale cream. Skin
and eye color are also diluted.
D
D
d
DD: Horse shows a diluted body color to pinkish-red,
yellow-red,
yellow or mouse gray and has dark points including
dorsal stripe,
shoulder stripe and leg barring.
Dd: Same as DD.
dd: Horse has undiluted coat color.
TO
TO
to
TOTO: Horse is characterized by white spotting pattern
known as
tobiano. Legs are usually white
Toto: Same as TOTO
toto: No tobiano pattern present.
The latest is that overo is also a dominant allele and is at a separate
locus from Tobiano so you can have a horse that is both overo and tobiano.
Oogie McGuire - oogiem@dsrtweyr.com
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