Despigmentación gris - Melanoma
La prueba de ADN verifica la presencia de la mutación gris. El gris es el gen dominante responsable de la despigmentación...
€40.00 IVA incluido
Acerca de la prueba
El Test de ADN para el color de pelaje gris detecta la mutación dominante Gris (G), responsable de la pérdida gradual de la pigmentación del pelaje a lo largo de la vida del caballo.
El gris es un modificador de color dominante que hace que los caballos de cualquier color base de pelaje se desvanezcan progresivamente, a menudo volviéndose casi completamente blancos con la edad. Esta prueba identifica si un caballo porta una o dos copias del gen Gris.
¿Por qué probar?
La prueba del gen Gris ayuda a:
- Confirmar si un caballo porta la mutación Gris.
- Identificar potros grises antes de que la despigmentación sea visible.
- Diferenciar caballos verdaderamente grises de caballos de color claro natural.
- Apoyar programas de cría que buscan producir o evitar descendencia gris.
- Determinar si un caballo gris es heterocigoto u homocigoto para el gen Gris.
Signos clínicos
Grey does not change the colour a foal is born with. It slowly removes the pigment from the hair as the horse gets older.
What a grey horse looks like:
- The foal is born bay, black, chestnut or any other colour
- White hairs appear and spread with age
- Some keep small coloured flecks all their life, known as flea-bitten grey
- Horses with two copies usually go grey faster, and keep fewer flecks, than horses with one copy
- The skin usually stays dark, though patches of pink, unpigmented skin are common
Melanoma. Grey horses develop skin melanomas much more often than other horses. Studies report them in 50 to 80% of grey horses aged 15 or older. They show as firm black lumps, most often under the tail, around the anus and genitals, and on the lips and eyelids. Most grow slowly and stay benign, but some spread.
A Grey result does not mean a horse has melanoma. Show any new lump to your veterinarian: only a veterinary examination can say what it is.
Transmisión
Grey is dominant. One copy is enough for a horse to turn grey. 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: no grey foals
- N/N x G/N gives 50% N/N, 50% G/N: one foal in two turns grey
- N/N x G/G gives 100% G/N: every foal turns grey
- G/N x G/N gives 25% N/N, 50% G/N, 25% G/G: three foals in four turn grey
- G/N x G/G gives 50% G/N, 50% G/G: every foal turns grey
- G/G x G/G gives 100% G/G: every foal turns grey
Grey does not skip a generation, even when both parents are grey.
Prevención
The result helps in two ways: planning matings and watching grey horses for melanoma.
Planning matings.
- For no grey foals, both parents must be free of Grey
- For a grey foal every time, use a parent with two copies
- To avoid foals with two copies, mate a grey horse to a partner free of Grey
Watching for melanoma. Ask your veterinarian to check the places listed under Clinical signs at routine visits. Treatment decisions belong to your veterinarian.
Colour should not be the only thing that decides a mating.
Resultados
La prueba de ADN verifica la presencia de la mutación gris y presenta los resultados como uno de los siguientes:
- N/ – Caballo no gris. Negativo para gris. El caballo no se volverá gris.
- G/N - Caballo gris. Positivo para el gen gris dominante, portando una copia heredada. El pelaje del portador se modifica y eventualmente se despigmentará. Los caballos grises heterocigotos tienen una probabilidad estadística de transmitir el gen al 50% de su descendencia cuando se reproducen.
- G/ - Caballo gris. Positivo para el gen gris dominante, portando dos copias heredadas. El pelaje del portador se modifica y eventualmente se despigmentará. Los caballos grises homocigotos están genéticamente obligados a transmitir el gen al 100% de su descendencia cuando se reproducen, por lo que todos los potros recibirán el gris y se desvanecerán.
Requisitos de muestra
5 mL - sangre - tubo K3 EDTA
Envía tu muestra por correo ordinario o entrega exprés a:
Laboratorio Equigerminal HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal
Tiempo de entrega
2 a 5 días hábiles
Cómo funciona
🛒 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.
Preguntas frecuentes
¿Qué detecta esta prueba?
La prueba detecta la mutación dominante Grey (G) responsable de la despigmentación progresiva del pelaje.
¿Puede un potro dar positivo antes de volverse gris?
Sí. Los potros portadores del gen Grey nacen con el color base de su pelaje y pueden no comenzar a volverse grises hasta varios meses o incluso años después.
¿Cuál es la diferencia entre G/N y G/G?
Un G/N caballo lleva una copia del gen Grey y tiene un 50% de probabilidad de transmitirlo a cada potro. Un G/G caballo lleva dos copias y transmitirá el gen Grey a toda su descendencia.
¿El gen Grey determina el color original del pelaje del caballo?
No. El gen Grey solo causa un desvanecimiento progresivo. El color base subyacente está determinado por otros genes como Extension, Agouti, Creamy Dun.
¿Por qué es útil la prueba de Grey para los criadores?
La prueba de ADN permite a los criadores predecir si los potros eventualmente se volverán grises y tomar decisiones informadas al seleccionar para o contra el rasgo Grey.
For Professionals
Genetic and clinical detail for veterinarians, geneticists and laboratories.
- Gene / locus: STX17 (syntaxin 17), Grey (G) locus, ECA25.
- Variant: cis-acting intronic copy-number variant of a 4.6 kb segment, increasing expression of STX17 and the neighbouring NR4A3 in pigment cells. HGVS (EquCab3.0): two copies (G2), NC_009168.3:g.6625295_6629872dup; three copies (G3), NC_009168.3:g.6625295_6629872[3].
- Alternative designations: described as a 4.6 kb duplication by Rosengren Pielberg et al. (2008); Rubin et al. (2024) showed that the segment occurs in two (G2) or three (G3) tandem copies, with different phenotypes. OMIA lists G2 and G3 as separate variants.
- Variant identifiers: no rs/EVA identifier listed in OMIA; OMIA variants 438 (G2) and 1732 (G3).
- Variant classification: not currently evaluated (ISAG/AVCG, per OMIA), both G2 and G3.
- Inheritance: autosomal dominant (OMIA code D).
- Penetrance / expressivity: present in all 727 grey and none of 131 non-grey horses (Rosengren Pielberg et al., 2008). G3: rapid greying, usually fully white by about 10 years, high melanoma risk. G2: greying from 5 to 7 years, never fully white; no melanoma in 25 G2 Connemara ponies aged 15 to 35 (Rubin et al., 2024). Zygosity: Lipizzaners with G/G had more severe melanomas (Rosengren Pielberg et al., 2008); melanoma in 27% of G/G versus 16% of G/N Quarter Horses (Teixeira et al., 2013).
- Melanoma prevalence: source for the figure under Clinical signs: Rubin et al. (2024). The often-quoted 70 to 80% of greys over 15 comes from earlier studies of Australian greys and Camargue mares, cited by Rosengren Pielberg et al. (2008). In 335 grey Quarter Horses: 16% at all ages, 52% over 15 years (Teixeira et al., 2013).
- Breeds with documented carriers or cases: the same variant, from one ancient ancestor, in grey Lipizzaner, Arabian, Connemara, Thoroughbred, Welsh pony, Icelandic horse, New Forest pony and Shetland pony (Rosengren Pielberg et al., 2008); grey Quarter Horses (Teixeira et al., 2013). Particularly common in the Lipizzaner and the Arabian. Among about 1,400 horses from 78 breeds, G3 was found in 62 populations and G2 in 8 (Rubin et al., 2024).
- Clinical / diagnostic notes for veterinarians: monitor predilection sites clinically and confirm masses histologically. ASIP genotype has been evaluated as a modifier of melanoma risk in grey Quarter Horses (Teixeira et al., 2013).
Key references:
- Rosengren Pielberg G, Golovko A, Sundstrom E, et al. (2008). A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse. Nat Genet 40:1004-1009. doi:10.1038/ng.185. PMID 18641652.
- Teixeira RBC, Rendahl AK, Anderson SM, et al. (2013). Coat color genotypes and risk and severity of melanoma in gray Quarter Horses. J Vet Intern Med 27:1201-1208. doi:10.1111/jvim.12133.
- Rubin CJ, Hodge M, Naboulsi R, et al. (2024). An intronic copy number variation in Syntaxin 17 determines speed of greying and melanoma incidence in Grey horses. Nat Commun 15:7510. doi:10.1038/s41467-024-51898-2. PMID 39209879.