Estensione, castano o sorrel
Test del DNA per il gene Extension che controlla la produzione di pigmento nero o rosso in tutto il mantello....
€43.05 incl. I.V.A.
Informazioni sul test
Il Test del DNA Extension (MC1R) determina il colore genetico del mantello identificando se un cavallo porta l'allele dominante del pigmento nero (E) o l'allele recessivo del pigmento rosso (e).
Questo test è essenziale per gli allevatori che desiderano prevedere i colori del mantello della prole e identificare i cavalli portatori del fattore rosso recessivo, anche quando mostrano un mantello a base nera.
Per una previsione completa del colore del mantello, si consiglia il test Extension insieme al test Agouti e ad altri test di diluizione del colore del mantello.
Perché testare?
Il test del gene Extension consente agli allevatori di:
- Identificare i portatori dell'allele rosso recessivo (castano).
- Prevedere il colore di base del mantello della futura prole.
- Migliorare le decisioni di allevamento per la selezione del colore.
- Confermare se i cavalli a base nera sono omozigoti o eterozigoti per il gene Extension.
- Combinare i risultati con i geni Agouti e di diluizione per una previsione completa del colore del mantello.
Segni clinici
This gene sets coat colour. It is not linked to any illness.
Horses that can make black pigment. Carriers and non-carriers look the same. Agouti then decides where the black goes: onto the legs, mane and tail only for a bay or brown, or all over for a black.
Chestnut horses. The coat has only red pigment. The shade runs from a pale sorrel to a very dark liver chestnut, and the mane and tail may be darker, the same shade or flaxen. Sorrel, chestnut and liver chestnut are names for the same result. Agouti has no black pigment to work on, so it does not change a chestnut.
What fools the eye:
- A very dark liver chestnut against a true black, especially in winter coat
- A sun-bleached black, which can read as dark brown or dark chestnut
- A flaxen chestnut against a palomino: both have a light mane and tail on a golden body
- A dilution on top of the base colour: Cream, Pearl, Champagne, Dun or Silver
- Grey, which slowly strips the base colour away and in the end hides it completely
Trasmissione
Chestnut is recessive. A horse needs one chestnut copy from the sire and one from the dam to be chestnut. The gene is not on a sex chromosome, so colts and fillies are the same.
What each mating can produce:
- E/E x E/E gives 100% E/E: no chestnut foals and no carriers
- E/E x E/e gives 50% E/E, 50% E/e: no chestnut foals
- E/E x e/e gives 100% E/e: no chestnut foals, every foal a carrier
- E/e x E/e gives 25% E/E, 50% E/e, 25% e/e: one foal in four chestnut
- E/e x e/e gives 50% E/e, 50% e/e: one foal in two chestnut
- e/e x e/e gives 100% e/e: every foal chestnut
Prevenzione
The result lets you plan whether a mating can give chestnut foals.
To get chestnut foals. Both parents must carry the chestnut variant. The crosses under Transmission give the odds.
To keep chestnut out. At least one parent must have no copy of the chestnut variant.
Breeding for black. Test both parents at Agouti too. Both must be able to pass on black.
Chestnuts and Silver. Silver only lightens black pigment, so a chestnut can carry Silver without showing it and pass it on unseen. In breeds where Silver occurs, keep this in mind: Silver is linked to an eye condition, Multiple Congenital Ocular Anomalies.
Colour should not be the only thing that decides a mating.
Risultati
Il test del DNA per il gene Extension verifica il colore del mantello di base e presenta i risultati come uno dei seguenti:
- E/E- Ommozigote dominante per Extension - Nero, Baio o Marrone - Viene espresso solo il fattore nero Il cavallo può trasmettere solo l'allele (E) E/E alla sua prole. Non può avere puledri con colore di base Castano o Sorrel indipendentemente dal colore del partner. Il gene Agouti determinerà se il colore di base sarà nero, baio o marrone, a meno che non sia modificato da altri geni modificatori del colore.
- E/e - Eterozigote per Extension - Nero, Baio o Marrone - Sia il fattore rosso che quello nero sono espressi. Può trasmettere sia l'allele (E) che (e) alla sua prole. Il gene Agouti determinerà se il colore di base sarà nero, baio o marrone, a meno che non sia modificato da altri geni modificatori del colore.
- e/e - Ommozigote recessivo per Extension - Castano o Sorrel- Viene espresso solo il pigmento rosso. Il colore di base è castano o sorrel a meno che non sia modificato da altri geni modificatori del colore.
Requisiti di esempio
30 a 40 - radici dei capelli - busta o 5 mL - sangue - tubo K3 EDTA
Invia il tuo campione tramite posta ordinaria o corriere espresso a:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portogallo
Tempi di consegna
2 a 5 giorni lavorativi
Come funziona
🛒 Acquista il Test: Seleziona e acquista il test online.
📧 Ricevi le Istruzioni: Dopo la conferma del pagamento, riceverai le istruzioni per la raccolta del campione.
✨ Raccolta del Campione: Raccogli 30–40 radici di capelli o chiedi al tuo veterinario di prelevare un campione di sangue.
📄 Scarica il Modulo di Invio: Scarica il modulo di invio stampabile.
📮 Invia i Campioni: Invia i tuoi campioni a:
Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portogallo
📄 Ricevi i Risultati: Il tuo certificato DNA sarà inviato via email.
Domande frequenti
What does this test not detect?
It does not read a second, much rarer chestnut variant called e-a. It does not test Agouti. It does not test Cream, Pearl, Champagne, Silver, Dun, Grey, Roan, Tobiano, Overo, Splashed White, Sabino, Dominant White or the Appaloosa patterns. It says nothing about health, performance or temperament.
My horse is chestnut. Do I still need the test?
Usually not, since a chestnut horse already has two chestnut copies. It still makes sense when the colour is hard to read.
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.
For Professionals
Genetic and clinical detail for veterinarians, geneticists and laboratories.
- Gene / locus: MC1R (melanocortin 1 receptor), Extension (E) locus, ECA3.
- Variant: e allele, c.248C>T, missense, loss of receptor function: the receptor no longer takes the hormone signal that switches the pigment cell to black pigment. HGVS (EquCab3.0): NC_009146.3:g.36979560C>T; NM_001114534.1:c.248C>T; NP_001108006.1:p.(Ser83Phe). Marklund et al. (1996) showed that chestnut in 12 breeds comes from this change.
- Alternative designations: chestnut, red factor. A second chestnut allele, e^a (NM_001114534.1:c.250G>A; NP_001108006.1:p.(Asp84Asn); NC_009146.3:g.36979562G>A; rs3443929753), was described in the Belgian Draft (Wagner and Reissmann, 2000) and is also reported in the Black Forest horse. Avila et al. (2022) concluded that detecting e^a matters when breeding to a colour.
- Variant identifiers: e: rs68458866 (EVA); OMIA variant 154. e^a: OMIA variant 155.
- Variant classification: not currently evaluated (ISAG/AVCG, per OMIA).
- Inheritance: autosomal recessive for the chestnut phenotype (e/e); E is dominant. OMIA code: A (autosomal). Recessive inheritance was first argued by Hurst (1906), disputed by Weldon the same year, and settled from studbook records in Hurst's favour.
- Breeds with documented carriers or cases: widespread. Avila et al. (2022) found e 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. e^a carriers: Knabstrupper 6/91, Paint Horse 1/2,076, Percheron 1/52, Quarter Horse 2/110 (Avila et al., 2022).
- Allele / carrier frequencies: allele frequency of e from 76% (Pony of the Americas) to 12% (Percheron) across 28 breeds (Avila et al., 2022; 11,281 horses tested, 6,878 after removal of close relatives). The authors 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 c.248C>T genotype only. An E/E or E/e horse from Belgian Draft, Knabstrupper, Paint, Percheron or Quarter Horse lines may still carry e^a; an e/e-like phenotype with an E/e result should prompt e^a testing. Source for the Silver note under Prevention: Brunberg et al. (2006). Mura et al. (2024) documented mismatch between genetic and recorded visual colour in the Sarcidano horse. Reported links between MC1R and behaviour (Jacobs et al., 2016; Finn et al., 2016) are early exploratory work and no basis for decisions.
Key references:
- Marklund L, Moller MJ, Sandberg K, Andersson L (1996). A missense mutation in the gene for melanocyte-stimulating hormone receptor (MC1R) is associated with the chestnut coat color in horses. Mamm Genome 7:895-899. PMID 8995760.
- Wagner HJ, Reissmann M (2000). New polymorphism detected in the horse MC1R gene. Anim Genet 31:289-290. doi:10.1046/j.1365-2052.2000.00655.x. PMID 11086549.
- 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.