Dilution crème
Le gène de dilution crème a des effets variés sur différentes couleurs de base. Pour obtenir le ‘nom de type’...
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À propos du test
Le gène de dilution crème a des effets variables selon les couleurs de base.
Pour obtenir le « nom de type » exact de la dilution crème du cheval, il est recommandé de réaliser ce test conjointement avec les gènes Extension et Agouti.
Pourquoi tester ?
Le test est utile lorsque la confirmation génétique est nécessaire ou pour définir les chevaux dilués crème par rapport à d'autres gènes ayant des effets similaires (comme la dilution champagne et le gris).
Réaliser ce test permettra de confirmer si un cheval est dilué crème. Comme mentionné, le gène de dilution crème a des effets variables selon les couleurs de base. Pour obtenir le « nom exact » du type de dilution crème du cheval (par exemple Buckskin, Palomino, Cremello…), il est recommandé de réaliser ce test en conjonction avec les facteurs rouge et agouti.
Signes cliniques
Cream lightens the coat. How it looks depends on the base colour and on the number of copies. With no copy, the base colour shows as it is.
One copy: red pigment lightened.
- Chestnut becomes palomino: a golden body with a white or flaxen mane and tail
- Bay becomes buckskin: a golden body with the black points kept
- Black becomes smoky black, which usually looks like an ordinary black
Two copies: red and black pigment lightened. The coat goes pale cream, the skin is pink and the eyes are blue.
- Chestnut becomes cremello
- Bay becomes perlino: a cream body with slightly darker, rust-tinged points
- Black becomes smoky cream
What fools the eye:
- Smoky black read as black. This is the commonest mistake with this gene.
- Palomino read as flaxen chestnut, and the other way round
- Cremello or perlino read as white or albino. These horses have cream hair and still make a little pigment. True white horses owe their colour to other genes.
- Buckskin read as bay dun, or the two present together
- Grey, which slowly strips any of these colours away
Health. No disease is linked to Cream. Blue eyes and pink skin are part of the colour, not a defect, and need no treatment.
Transmission
Cream shows with one copy, and shows more with two. The gene is not on a sex chromosome, so colts and fillies are the same.
What each mating can produce:
- N/N x N/N gives 100% N/N
- N/N x N/Cr gives 50% N/N, 50% N/Cr
- N/N x Cr/Cr gives 100% N/Cr
- N/Cr x N/Cr gives 25% N/N, 50% N/Cr, 25% Cr/Cr
- N/Cr x Cr/Cr gives 50% N/Cr, 50% Cr/Cr
- Cr/Cr x Cr/Cr gives 100% Cr/Cr
Prévention
The result lets you plan which dilute colours a mating can give.
To guarantee a dilute foal. Use a parent with two copies.
To get a palomino. The foal needs one Cream copy on a chestnut base. Cremello put to chestnut gives only palominos.
To get a buckskin. The foal needs one Cream copy on a bay base. Cremello put to bay is the most efficient route, and the outcome then depends on the bay parent's own base colour genes.
To avoid a double dilute. Mate a Cream carrier only with a partner that tested negative.
Résultats
Le test ADN vérifie la présence du gène de dilution Cream et présente les résultats comme l'un des suivants :
- N/ - Non dilué. Les couleurs de base sont noir, bai ou alezan, en l'absence d'autres gènes modificateurs.
- N/Cr – Dilué. Hétérozygote, une copie de l'allèle Cream (Cr). Alezan est dilué en palomino; bai est dilué en buckskin et noir est dilué en noir fumé. Ces couleurs peuvent être modifiées davantage par l'action d'autres gènes.
- Cr/ - Double dilution, deux copies de l'allèle Cream (Cr). L'alezan est dilué en cremello; le bai est dilué en perlino et le noir est dilué en smoky cream.
Exigences d'échantillon
30 à 40 - racines de cheveux - enveloppe ou 5 mL - sang - tube K3 EDTA
Envoyez votre échantillon par courrier ordinaire ou livraison express à :
Laboratoire Equigerminal HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
Délai d'exécution
2 à 5 jours ouvrables
Comment ça marche
🛒 Purchase the test: select and buy the test online.
📧 Receive instructions: after payment confirmation you receive sample collection instructions by e-mail.
✨ Collect the sample yourself: pull 20 to 40 hair roots with the bulb attached, or ask your veterinarian to collect blood in a K3-EDTA tube.
📄 Complete the form: print and complete the submission form with the animal identification.
📮 Send it to the laboratory: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.
📄 Receive your report: your certified report is issued as soon as the analysis is validated.
Questions fréquentes
What does this test not detect?
It reads Cream only. It does not read Pearl, Sunshine or Snowdrop, three other dilutions in the same gene. It does not test Champagne, Silver, Dun, Grey, Mushroom, any white pattern or the base colour. It says nothing about health, performance or temperament.
At what age can a horse be tested?
Any age. The genotype is fixed at conception and never changes. A foal coat is a poor guide to dilution, so testing early makes sense.
Should I also test for Pearl?
Yes, if the horse is pale and the Cream result does not explain it, or if it is of Iberian or stock-horse origin, where Pearl occurs and can imitate Cream. Where relevant, test Champagne too.
For Professionals
Genetic and clinical detail for veterinarians, geneticists and laboratories.
- Gene / locus: SLC45A2 (solute carrier family 45 member 2; formerly MATP), Cream (C) locus, ECA21.
- Variant: C^Cr allele, missense. HGVS (EquCab3.0): NC_009164.3:g.31690653G>A; XM_001498110.4:c.601G>A; XP_001498160.2:p.(Asp201Asn).
- Alternative designations: published as exon 2 c.457G>A, p.Asp153Asn (Mariat et al., 2003). The genomic position is the same; c. and p. numbering differ because OMIA uses a more recent RefSeq transcript.
- Variant identifiers: rs1140980396 (EVA); OMIA variant 153.
- Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
- Mechanism: SLC45A2 encodes a transporter the melanocyte needs to function; the Cream variant reduces the pigment deposited in the hair.
- Inheritance: autosomal incomplete dominant (dosage effect): one copy dilutes phaeomelanin, two copies dilute phaeomelanin and eumelanin. OMIA code: A (autosomal).
- Breeds with documented carriers or cases: OMIA variant record lists Quarter Horse, Morgan and Welsh Pony. Avila et al. (2022) found Cream in 25 of 28 breeds: Andalusian, Appaloosa, Arabian, Connemara Pony, Dutch Warmblood, Gypsy Cob, Gypsy Vanner, Icelandic Horse, Lusitano, Miniature Horse, Missouri Fox Trotter, Morgan Horse, Mustang, Norwegian Fjord Horse, Oldenburg, Paint Horse, Pony of the Americas, Pura Raza Espanola, Quarter Horse, Rocky Mountain Horse, Shetland Pony, Standardbred, Tennessee Walking Horse, Thoroughbred and Welsh Pony. Not detected in Hanoverian (n=31), Knabstrupper (n=71) or Percheron (n=37); absence in a sample does not prove absence in the breed.
- Allele / carrier frequencies: allele frequency from 42% in the Lusitano (n=102) to 1.3% in the Standardbred (n=39), Iberian breeds among the highest (Avila et al., 2022; 11,281 horses tested, 6,878 after removing close relatives). The authors note ascertainment bias, as samples were submitted for colour testing, so figures for less-sampled breeds may be overestimated.
- Clinical / diagnostic notes for veterinarians: SLC45A2 carries at least four equine dilution alleles: Cream, Pearl (Sevane et al., 2019), Sunshine (Holl et al., 2019) and Snowdrop (Bisbee et al., 2020).
Key references:
- Mariat D, Taourit S, Guerin G (2003). A mutation in the MATP gene causes the cream coat colour in the horse. Genet Sel Evol 35:119-133. doi:10.1051/gse:2002039. PMID 12605854.
- Locke MM, Ruth LS, Millon LV, Penedo MCT, Murray JD, Bowling AT (2001). The cream dilution gene, responsible for the palomino and buckskin coat colours, maps to horse chromosome 21. Anim Genet 32:340-343.
- Holl HM, Pflug KM, Yates KM, Hoefs-Martin K, Shepard C, Cook DG, Lafayette C, Brooks SA (2019). A candidate gene approach identifies variants in SLC45A2 that explain dilute phenotypes, pearl and sunshine, in compound heterozygote horses. Anim Genet 50:271-274. doi:10.1111/age.12790. PMID 31006892.
- Avila F, Hughes SS, Magdesian KG, Penedo MCT, Bellone RR (2022). Breed distribution and allele frequencies of base coat color, dilution, and white patterning variants across 28 horse breeds. Genes 13:1641.