Test ADN Agouti - Bai / Noir
Le locus Agouti contrôle la distribution du pigment noir dans le pelage. Ce test ADN détermine si un cheval est...
€43.05 BEZa barne
À propos du test
Agouti locus contrôle la répartition du pigment noir sur le pelage.
Ce test ADN détermine si un cheval est A/A, A/a ou a/a pour l'Agouti.
Pour déterminer la couleur de base, les tests Extension et Agouti sont nécessaires.
Achetez le test de couleur de base et obtenez les tests ADN pour les loci Agouti (A) et Extension (E). loci.
Pourquoi tester ?
L'agouti ne se manifeste pas physiquement chez les chevaux alezans (e/e). Par conséquent, un éleveur pourrait vouloir tester un cheval de base alezan pour voir s'il est porteur de l'agouti.
Il peut être souhaitable de tester les chevaux bai pour déterminer s'ils portent une (A/a) ou deux (A/A) copies de l'allèle Agouti. Un cheval homozygote Agouti (A/A) transmettra toujours l'agouti à sa descendance, tandis qu'un hétérozygote (A/a) aura 50 % de chances de transmettre ce gène.
Une autre raison de tester l'agouti pourrait être le doute quant à savoir si un cheval noir est vraiment noir ou un bai très foncé. Les effets d'autres gènes peuvent également rendre difficile la détection de la présence de l'agouti.
Signes cliniques
This gene sets coat colour. No illness is linked to it. The looks below apply to a horse that can make black pigment, which is decided by Extension.
Bay horses. Black is kept to the points: mane, tail, lower legs and the rims of the ears. The body runs from light to very dark red-brown. Carriers of black look the same as non-carriers.
Black horses. Black covers the whole horse, mane, tail and legs included.
Chestnut horses. A chestnut makes no black pigment, so this gene has nothing to act on. A chestnut looks the same whatever it carries here.
Seal brown. Seal brown, black-and-tan or dark brown horses are a recognised type. No gene change for it has been confirmed in the horse, so this test does not separate seal brown from bay.
What fools the eye:
- A very dark bay or a seal brown against a true black
- A black coat faded by sun, sweat or a winter coat, which reads as brown
- Sooty shading, which darkens a bay body along the back
- A dilution on top of the base colour, which can make the black points hard to see
- Grey, which slowly strips the base colour away and in the end hides it completely
Transmission
Black is recessive. A horse needs one black copy from the sire and one from the dam. The gene is not on a sex chromosome, so colts and fillies are the same.
What each mating can produce:
- A/A x A/A gives 100% A/A: no black foals and no carriers
- A/A x A/a gives 50% A/A, 50% A/a: no black foals
- A/A x a/a gives 100% A/a: no black foals, every foal a carrier
- A/a x A/a gives 25% A/A, 50% A/a, 25% a/a: one foal in four a/a
- A/a x a/a gives 50% A/a, 50% a/a: one foal in two a/a
- a/a x a/a gives 100% a/a: every foal a/a
Prévention
The result lets you plan for bay or black foals.
To get black foals. Two things must line up. Both parents must carry the black version, and the foal must also inherit at least one working copy at Extension. Two black parents that carry no chestnut give only black foals. Two black parents that each carry chestnut give three black foals in four and one chestnut.
To keep black out. At least one parent must have no copy of the black version.
Do not assume a chestnut parent is safe. A chestnut mare can carry two copies of the black version and pass one to every foal. Put to a black stallion she can produce black foals, even if she has never had one. A line can carry black this way for generations without a black foal.
Breeding for a dilute colour. This gene decides which dilute you get. Bay plus one Cream gives a buckskin, black plus one Cream a smoky black, bay plus Dun a bay dun and black plus Dun a grullo.
Colour should not be the only thing that decides a mating.
Résultats
- A/A - Bai ou brun - Homozygote dominant pour Agouti. Pigment noir limité aux extrémités. Le cheval ne peut pas avoir de poulains noirs, quel que soit la couleur de robe du partenaire. La couleur de base sera bai ou brun en l'absence d'autres gènes modificateurs de couleur.
- A/a - Bai ou brun - Hétérozygote pour Agouti. Pigment noir réparti selon le motif des extrémités. Le cheval peut transmettre soit l'allèle (A) soit l'allèle (a) à sa descendance. La couleur de base sera bai ou brun sauf modification par d'autres gènes modificateurs de couleur.
- a/a - Noir - Homozygote récessif pour Agouti. Pigment noir réparti uniformément. La couleur de base sera noire en l'absence d'autres gènes modificateurs de couleur.
Exigences d'échantillon
30 à 40 racines de cheveux ou 5 mL de sang dans un 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
Traitement standard - Résultats en 3 à 5 jours ouvrables après réception de l'échantillon au laboratoire. Les clients organisent et prennent en charge les frais d'envoi des échantillons au laboratoire.
Traitement PREMIUM - Résultats en 1 jour après réception de l'échantillon. Comprend la livraison express gratuite**. Le laboratoire organise l'expédition express avec prise en charge du colis à l'adresse du client et livraison au laboratoire.
LES SERVICES PREMIUM INCLUENT UNE LIVRAISON PAR EXPÉDITION EXPRESS POUR LES PAYS EUROPÉENS NON RÉGIONS ISOLÉES.
Vérifiez ici si vous êtes dans une région européenne isolée.
Des frais supplémentaires sont appliqués pour les régions isolées/éloignées.
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 does not test Extension, Cream, Pearl, Champagne, Silver, Dun, Grey, Roan, Tobiano, Overo, Splashed White, Sabino, Dominant White or the Appaloosa patterns. It does not assess melanoma risk, and it says nothing about health, performance or temperament.
My black horse tested A/a. How?
Look at the colour again before doubting the result. A carrier that can make black pigment is bay, not black (see What fools the eye under Clinical signs). If the horse really is black all over, flanks and muzzle included, ask the laboratory to repeat it from a fresh sample.
At what age can a horse be tested?
Any age. The result never changes, so a newborn foal gives the same answer as an adult. That helps here, because a foal coat is a poor guide to the adult colour.
For Professionals
Genetic and clinical detail for veterinarians, geneticists and laboratories.
- Gene / locus: ASIP (agouti signalling protein), Agouti (A) locus, ECA22.
- Variant: a allele, 11-bp deletion causing a frameshift that breaks the signal switching the follicle from black to red pigment. In a bay the signal reaches the body but not the points; without it, black covers the whole coat. HGVS (EquCab3.0): NC_009165.3:g.26067463_26067473del; NM_001164017.1:c.187_197del. Rieder et al. (2001) found it behind recessive black in nine breeds.
- Alternative designations: published as g.2174_2184del and c.191_201del (Rieder et al., 2001); OMIA updated the coordinates to the current reference genome, giving c.187_197del.
- Variant identifiers: rs3091770233 (EVA); OMIA variant 509.
- Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
- Inheritance: autosomal recessive for the black phenotype (a/a); A is dominant. OMIA code: A (autosomal).
- Breeds with documented carriers or cases: widespread. Avila et al. (2022) found a in all 28 breeds studied: Andalusian, Appaloosa, Arabian, Connemara Pony, Dutch Warmblood, Gypsy Cob, Gypsy Vanner, Hanoverian, Icelandic Horse, Knabstrupper, Lusitano, Miniature Horse, Missouri Fox Trotter, Morgan Horse, Mustang, Norwegian Fjord Horse, Oldenburg, Paint Horse, Percheron, Pony of the Americas, Pura Raza Espanola, Quarter Horse, Rocky Mountain Horse, Shetland Pony, Standardbred, Tennessee Walking Horse, Thoroughbred and Welsh Pony.
- Allele / carrier frequencies: allele frequency of a (Avila et al., 2022; 11,281 horses tested, 6,878 after removal of close relatives, 28 breeds): Percheron 99% (n=37), Gypsy Vanner 92% (n=67), Rocky Mountain Horse 87% (n=117), Tennessee Walking Horse 86% (n=181), Gypsy Cob 82% (n=60); lowest in Thoroughbred 24% (n=66) and Norwegian Fjord 24% (n=90). The authors describe a as nearly universal in the Percheron, a breed selected for black and grey, and note ascertainment bias, since samples were submitted for colour testing, so figures for less-sampled breeds may be overestimated.
- Clinical / diagnostic notes for veterinarians: the report gives the ASIP deletion genotype only. ASIP genotype has been evaluated as a modifier of melanoma risk and severity in grey Quarter Horses (Teixeira et al., 2013); that question also needs the Grey genotype (see the Melanoma test). Mura et al. (2024) documented mismatch between genetic and recorded visual colour in the Sarcidano horse.
Key references:
- Rieder S, Taourit S, Mariat D, Langlois B, Guerin G (2001). Mutations in the agouti (ASIP), the extension (MC1R), and the brown (TYRP1) loci and their association to coat color phenotypes in horses. Mamm Genome 12:450-455. doi:10.1007/s003350020017. PMID 11353392.
- 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.
- Teixeira RB, Rendahl AK, Anderson SM, Mickelson JR, Sigler D, Buchanan BR, Coleman RJ, McCue ME (2013). Coat color genotypes and risk and severity of melanoma in gray Quarter horses. J Vet Intern Med 27:1201-1208.