The Pearl color varieties and their genetics
It is believed that pearl and cream are alleles at the
same locus.
Thus, this site will use these three abbreviations for the three
possible alleles at the cream locus:
prl (pearl gene), Cr (cream gene)* and cr (neither)
Pearl and "neither" are represented LOWER-CASE because
they are recessive to cream.
Cream* is represented with the upper case "Cr" because it is a(n
incomplete) dominant gene.
(The notations in parentheses with "N" in them are
used by some laboratory reports,
and are only included here to help readers interpret those reports.)
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cr cr
= no pearl and no cream* gene present
(N/N)
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This horse will have no change in its coat
or skin color due to either
the pearl or cream genes. It may be a solid dark
color,
or it may have variations caused by OTHER color modifying
genes.
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If bred, it will pass NEITHER a cream nor a
pearl gene to its foal.
If a foal from this horse has a cream or a pearl gene, it
has to
have come from the other parent.
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prl cr = one pearl gene,
no cream* gene (Prl/N)
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This horse will look almost identical the
one above,
except the coat color may be the slightest bit lighter,
almost like a lighter shade of the dark color,
and the dark skin may have pink dots in places.
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If bred, this horse has a 50% chance of
passing along the pearl gene to each foal.
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Cr prl = one cream and
one pearl gene [(Cr/N) and (Prl/N)]
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This horse will look similar to a
double-cream* or champagne color when it's born.
This means blue eyes, pink skin, and a distinctly diluted
coat color. As it matures,
the coat will lighten more, to almost a completely
double-cream diluted color.
The skin will develop freckles similar to champagne, but
muted in contrast.
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If bred, this horse will always pass along
one or the other gene to its foals.
Each foal has a 50% chance of inheriting the cream gene, and
a 50% chance
of inheriting the pearl gene, but NEVER BOTH, and ALWAYS ONE
OR THE OTHER.
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The foal's appearance will depend upon
which gene the cream pearl has passed on to it,
and what other genes the other parent has passed on to it.
Depending upon what genes it gets from its other parent,
it could be a double-cream, a homozygous pearl,
a single cream or a single pearl.
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prl prl = two pearl
genes; homozygous for pearl (Prl/Prl)
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This horse will be born with blue eyes and
purplish pink skin,
and a moderately diluted coat color.
As the foal matures, the skin may darken to a deeper
purplish pink,
and will develop freckles much like champagne freckles.
The coat (hair) color may lighten a bit with maturity,
but will not become as light as a double-cream* or a pearl
cream dilute.
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If bred, this horse will always pass along
one pearl gene. However, as always
with pearl, its presence will scarcely be noticeable unless
the foal also inherits
a pearl gene or a cream gene from its other parent.
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If two horses with prl,prl (two pearl genes
each, or each homozygous for pearl)
are bred together, the foals will ALWAYS have two pearl
genes (prl, prl).
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Examples
cr cr - No cream, no pearl.
No examples are shown here, at least as yet, since the variety
possible
from all other color modifying genes is so great!
prl cr - One pearl only
Also called single pearl, pearl, or pearl carrier. Some of
the APHA (Barlink, etc.) horses of this type have the pink dots on
their skin, and some of the Iberians of this type have slightly
lighter coat and eye color than normal. I will endeavor to add
pictures of both, and also pictures of single-pearls with no
discernible dilution, like RD Chica.
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This is RD Chica, the first Iberian pearl-carrier ever
identified. This mare was DNA tested to rule out her being
a smoky black, as she appears, and was found to be "just a
chestnut". Obviously, the slight dilution caused by a
single pearl gene was not enough to overcome her extremely dark
"liver chestnut" base color. Perhaps she would have been
even a little darker without the pearl gene.
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The Peruvian Paso mare in this photo has only one pearl gene.
Cr prl - Cream pearl
Depending upon the "base" color of the horse (red or black-based),
this combination produces particular, predictable effect. The skin
and eye color is usually the same (described above) regardless of the
base color.
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On chestnut (red based): the horse will end up looking like a
pale Palomino.
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On bay, brown or black (black-based): the horse will end up
looking like a pale buckskin with tan or brown points instead of
black.
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This Peruvian Paso filly is a SMOKY BLACK
PEARL. This color is the result of one pearl and one cream
gene acting on a solid black base. She is believed to be
the only horse of her color in New Zealand.
Heather Batkin, her breeder, writes that this filly is:
"...out of my Black/Pearl mare. Born 10th Dec 2009 8pm. She's a
smoky black pearl..."
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Guindaleza R is a PALOMINO PEARL, which is one pearl and one cream gene on a
chestnut base. She's the daughter of Chica (see above) by
Saphiro, a cremello. Owned by Sommer
Ranch.
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The first Pearl dilute that was ever discovered by this
webmaster was Majodero R, another SMOKY BLACK PEARL (solid black
plus one cream gene plus one pearl gene.) He was exported
from the USA to Australia, where we believe he still lives. E_aaCrcr
(DNA) IALHA #5987SP,
foaled May 30, 2001 out of RD Chica, a liver chestnut pearl carrier;
sired by
Q, a perlino.
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prl prl - double, or homozygous pearl
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Avispado, in Spain, is the first horse of this color ever
discovered by this webmaster. He was first presented to her as a
possible champagne, which, sadly, his owner still calls him to
this day. He is, however, something even rarer.
Having DNA tested E, aa, prlprl ... he's a solid black based
homozygous (double) pearl.
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