Name: Test del DNA Agouti - Baio / Nero
Brand: Equigerminal
Price: 43.05 EUR

Informazioni sul test

Agouti locus controlla la distribuzione del pigmento nero su tutto il mantello.

Questo test del DNA determina se un cavallo è A/A, A/a o a/a per l'Agouti.

Per determinare il colore di base sono necessari i test Extension e Agouti.

Acquista il test del colore di base e ottieni i test del DNA per i loci Agouti (A) ed Extension (E). loci.

Perché testare?

L'agouti non si manifesta fisicamente nei cavalli rossi (e/e). Pertanto, un allevatore potrebbe voler testare un cavallo con base castana per verificare se è portatore dell'agouti.

Potrebbe essere utile testare i cavalli baio per vedere se il cavallo porta una (A/a) o due (A/A) copie dell'allele Agouti. Un cavallo omozigote Agouti (A/A) trasmetterà sempre l'Agouti ai suoi discendenti, mentre un cavallo eterozigote (A/a) avrà il 50% di probabilità di trasmettere il gene.

Un altro motivo per testare l'Agouti potrebbe essere il dubbio se un cavallo nero sia veramente nero o un baio molto scuro. Gli effetti di altri geni potrebbero inoltre rendere difficile stabilire se l'Agouti è presente o meno.

Segni clinici

Bay (A/- E/-). The dominant A allele restricts black pigment to the points: mane, tail, lower legs and ear rims. The body ranges from light bay to very dark bay.

Black (a/a E/-). Uniform black over the whole horse, including mane, tail and legs.

Chestnut (-/- e/e). Red pigment only, from light chestnut to very dark chestnut, with a mane and tail that are darker, the same shade or flaxen. Agouti has no visible effect on a -/- e/e horse.

The base coat alone does not dictate the horse's coat, because there are many other genes that modify the base coat: they can dilute it, depigment it or add white spotting or other patterns to it. Phenotypes that can be confused:

Very dark bay (A/- E/-) and black (a/a E/-)
Black (a/a E/-) faded by the sun
Very dark chestnut (-/- e/e) and black (a/a E/-)
Sooty, which darkens the back
Dilutions, which change the base coat
Grey, which progressively depigments the base coat

Trasmissione

What breeders need to know about base coat colour:

Two black base colour a/a E/e horses mated together can produce foals with a black (a/a E/-) or chestnut (a/a e/e) base colour.
Two chestnut base colour (-/- e/e) horses mated together can only produce foals with a chestnut base colour (-/- e/e).
Two bay base colour A/a E/e horses mated together can produce foals with a bay (A/- E/-), black (a/a E/-) or chestnut (-/- e/e) base colour.
A bay base colour A/A E/E horse can never produce foals with a black (a/a E/-) or chestnut (-/- e/e) base colour, whatever the mating partner.

Mendelian probability for each foal from mating two bay base colour A/a E/e horses:

56.25% bay base colour: A/- E/-
18.75% black base colour: a/a E/-
25% chestnut base colour: -/- e/e

Why is it so important to test bay and black base colour horses?

Because horses with the same base colour can have different genotypes, and that changes the foals they can produce.

Bay base colour horses:

A/A E/E: only produces foals with a bay base colour (A/- E/-), whatever the mating partner.
A/a E/E: carries the recessive a allele. Never produces foals with a chestnut base colour (-/- e/e). Mated with another carrier of the a allele, or with an a/a horse, it can produce foals with a black base colour (a/a E/-).
A/A E/e: carries the recessive e allele. Never produces foals with a black base colour (a/a E/-). Mated with another carrier of the e allele, or with a -/- e/e horse, it can produce foals with a chestnut base colour (-/- e/e).
A/a E/e: carries the recessive a allele and the recessive e allele. Can produce foals with a bay (A/- E/-), black (a/a E/-) or chestnut (-/- e/e) base colour.

Black base colour horses:

a/a E/E: never produces foals with a chestnut base colour (-/- e/e), whatever the mating partner.
a/a E/e: carries the recessive e allele. Mated with another carrier of the e allele, or with a -/- e/e horse, it can produce foals with a chestnut base colour (-/- e/e).

By appearance, these horses are identical. Only the DNA test shows which is which.

And that is why it is important to choose the mating partner carefully.

Prevenzione

100% probability of foals with a chestnut base coat -/- e/e. Both parents must have a chestnut base coat -/- e/e. The parents' Agouti genotype does not change the foal's base coat, but it is passed on.

Foals with a black base coat a/a E/-. Each parent must have at least one recessive a allele (A/a or a/a) and at least one of the parents must have the E allele. For a 100% probability of foals with a black base coat, both parents must be a/a and at least one must be E/E. Two a/a E/e horses mated together: 75% black base coat a/a E/- and 25% chestnut base coat a/a e/e.

100% probability of foals with a bay base coat A/- E/-. At least one parent must be A/A and at least one parent must be E/E. An A/A E/E horse produces 100% foals with a bay base coat, whatever the mating partner.

Base coat selection. To select against a chestnut base coat, use at least one E/E parent. To select against a black base coat, use at least one A/A parent.

The Agouti genotype of a chestnut base coat horse matters. An a/a e/e horse passes the a allele to 100% of its foals. Mated with a black base coat a/a E/E horse, it produces 100% foals with a black base coat a/a E/e.

Base coat should not be the only criterion for choosing a mating partner.

Risultati

A/A - Baio o Bruno - Ommozigote dominante per AgoutiPigmento nero limitato alle estremità. Il cavallo non può avere puledri neri indipendentemente dal colore del mantello del partner. Il colore di base del mantello sarà baio o bruno in assenza di altri geni modificatori del colore.
A/a - Baio o Bruno - Eterozigote per Agouti. Pigmento nero distribuito secondo il modello delle estremità. Il cavallo può trasmettere l'allele (A) o (a) ai suoi discendenti. Il colore di base del mantello sarà baio o bruno a meno che non sia modificato da altri geni modificatori del colore del mantello.
a/a - Nero - Ommozigote recessivo per AgoutiPigmento nero distribuito uniformemente. Il colore di base del mantello sarà nero in assenza di altri geni modificatori del colore.

Requisiti di esempio

30-40 radici di capelli o 5 mL di sangue in una provetta K3 EDTA

Tempi di consegna

Elaborazione standard - Risultati in 3-5 giorni lavorativi dopo l'arrivo del campione in laboratorio. I clienti organizzano e sostengono i costi di invio dei campioni al laboratorio.

Elaborazione PREMIUM - Risultati in 1 giorno dopo l'arrivo del campione. Include consegna espressa gratuita**. Il laboratorio organizza la spedizione Express con ritiro del pacco all'indirizzo del cliente e consegna al laboratorio.

I SERVIZI PREMIUM INCLUDONO UNA CONSEGNA ESPRESSA PER I PAESI EUROPEI NON REMOTI.

Controlla qui per sapere se ti trovi in una regione europea remota.

Per le regioni remote/isolated si applicano costi EXTRA.

Come funziona

🛒 Acquista il test: seleziona e acquista il test online.

📧 Ricevi le istruzioni: dopo la conferma del pagamento, ricevi via e-mail le istruzioni per il prelievo del campione.

📄 Compila il modulo: stampa e compila il modulo di invio campioni con l’identificazione dell’animale.

✨ Raccogli il campione: strappa da 20 a 40 radici di pelo con il bulbo e incollale nell’area indicata del modulo, oppure chiedi al tuo veterinario di prelevare il sangue in una provetta K3-EDTA.

📮 Invialo al laboratorio: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.

📊 Ricevi il referto: il referto certificato viene emesso non appena l’analisi è convalidata.

Domande frequenti

What is the difference between genotype and phenotype?
The genotype is what is written in the horse's DNA. It cannot be seen. The phenotype is what can be seen: in this case, the coat.
For each gene, the horse has two alleles: one inherited from the dam and one from the sire. We write, for example, A/a E/e.
Two horses can look the same and be different in their DNA. An A/A E/E horse and an A/a E/e horse both have a bay base coat. The A/a E/e horse can have foals with a black or chestnut base coat; the A/A E/E horse only has foals with a bay base coat.

What is the difference between base coat and the animal's coat?
The base coat is the starting point. There are only three: bay, black and chestnut. It is decided by two genes, Agouti and Extension.
Then other modifier genes can change the base coat: dilute it (make it lighter), depigment it (remove colour) or add white spotting and other patterns. The end result is the animal's coat, the one we see.
Examples:
• Palomino: chestnut base coat with one Cream allele.
• Buckskin: bay base coat with one Cream allele.
• Grey: any of the three base coats, progressively depigmented by Grey with age.
If the other modifier genes have no variants, the animal's coat is the same as the base coat.

What does each locus do?
The horse can produce two pigments: black pigment and red pigment.
Extension decides which one is produced. With at least one E allele, the horse produces black pigment. With e/e, the horse only produces red pigment.
Agouti decides where the black pigment goes. With at least one A allele, black pigment stays only on the points (mane, tail, lower legs and ear rims): bay base coat. With a/a, black pigment covers the whole body: black base coat.

Why is an e/e horse always chestnut base coat?
An e/e horse only produces red pigment. Agouti only acts on black pigment. Without black pigment, Agouti has nothing to act on, and the horse has a chestnut base coat -/- e/e, whatever its Agouti. But the Agouti alleles remain in the DNA and are passed on to the foals.

Why is an a/a horse black base coat only if it has the E allele?
a/a puts black pigment over the whole body. But there is only black pigment if the horse has at least one E allele. So: a/a E/- is black base coat; a/a e/e is chestnut base coat.

What does the dash in A/- or -/- mean?
The dash means "any allele". It is used when that allele does not change the base coat.
• A/- E/- can be A/A E/E, A/a E/E, A/A E/e or A/a E/e: all have a bay base coat.
• -/- e/e can be A/A e/e, A/a e/e or a/a e/e: all have a chestnut base coat.

If I can already see my horse's coat, what is the test for?
Because looking at the horse does not show what it can pass on to its foals. An A/A E/E horse and an A/a E/e horse look the same, but have different foals. Only the DNA test shows which is which.

Can two bay base coat horses mated together have a foal with a black or chestnut base coat?
Yes, if both are A/a E/e. Mendelian probability for each foal:
• 56.25% bay base coat A/- E/-
• 18.75% black base coat a/a E/-
• 25% chestnut base coat -/- e/e

Can two black base coat horses mated together have a foal with a chestnut base coat?
Yes, if both are a/a E/e. Mendelian probability for each foal:
• 75% black base coat a/a E/-
• 25% chestnut base coat a/a e/e

Which horse has 100% foals with a bay base coat?
An A/A E/E horse. It always passes the A allele and the E allele to every foal. So all foals have a bay base coat A/- E/-, whatever the other parent.

How to get foals with a black base coat?
For it to be possible: each parent must have at least one a allele, and at least one of the parents must have the E allele.
For a 100% probability: both parents must be a/a and at least one must be E/E.

Why does this test matter to breeders of black horses?
The Friesian horse is always black. In Portugal, the Coudelaria Ortigão Costa breeds only black Pure Blood Lusitano horses. To keep a black base coat in every foal, the breeder must know which breeding horses are a/a E/E and which carry the e allele (a/a E/e). Two a/a E/e horses mated together have a 25% probability of a foal with a chestnut base coat a/a e/e. An a/a E/E stallion has 100% foals with a black base coat with any a/a mare. Only the DNA test identifies the carriers.

Can a chestnut base coat horse have foals with a black base coat?
Yes, if it has the a allele (A/a e/e or a/a e/e). Example: an a/a e/e horse mated with an a/a E/E horse has 100% foals with a black base coat a/a E/e. That is why the Agouti of a chestnut base coat horse counts when choosing the mating partner.

How to tell a very dark bay base coat from a black base coat?
By eye it can be difficult. With the DNA test it is certain: bay base coat A/- E/-; black base coat a/a E/-.

My grey horse does not show its base coat. Can it be tested?
Yes. Grey progressively depigments the coat with age, but the DNA does not change. The test determines the base coat the horse was born with.

At what age can a horse be tested?
At any age. The DNA is the same from birth.

When will I receive the results?
Within 5 to 10 working days of the sample arriving at the laboratory. The certified report is sent as soon as the analysis is validated.

For Professionals

Genetic information for veterinarians, geneticists and laboratories.

Agouti (A) locus – ASIP gene (agouti signalling protein), ECA22

Function: controls the distribution of black pigment. The ASIP protein blocks the MC1R receptor.
A allele: functional dominant allele. Restricts black pigment to the points.
a allele: recessive allele. In a/a E/-, black pigment is distributed over the whole body.

Variant at the Agouti locus

a (Rieder et al., 2001): 11-bp deletion. NC_009165.3:g.26067463_26067473del; NM_001164017.1:c.187_197del. Originally published as g.2174_2184del and c.191_201del (Rieder et al., 2001); OMIA gives c.187_197del. Identifiers: rs3091770233; OMIA variant 509.

Inheritance

The e and a alleles are autosomal recessive (OMIA: code A, autosomal).

Breed distribution

Avila et al. (2022) tested 11,281 horses from 28 breeds and found the e and a alleles in all of them: 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 Española, Quarter Horse, Rocky Mountain Horse, Shetland Pony, Standardbred, Tennessee Walking Horse, Thoroughbred and Welsh Pony.

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.
Henner J, Poncet PA, Aebi L, Hagger C, Stranzinger G, Rieder S (2002). Horse breeding: genetic tests for the coat colors chestnut, bay and black. Schweiz Arch Tierheilkd 144:405-412.