Sire Dun Smoky Black on dam Roan Bay
In this article, we will explore the genetic possibilities of coat colors for the crossing between a stallion Dun Smoky Black and a mare Roan Bay. Equine genetics is a universe of combinations where dominant and recessive alleles determine the final coat of each individual.
On one side, we have the stallion Dun Smoky Black. Genetically, it presents the base genotype E/_ a/a Cr/n D/n. The Dun gene acts on the base color, adding the characteristic dark dorsal stripe. In some cases it lightens the body tone and may also produce zebra-like leg markings. This coat is based on Smoky Black.
On the other side, the mare Roan Bay contributes with its genetics based on E/_ A/_ Rn/n. The (Rn) gene acts on the base coat by distributing white hairs throughout the body, giving it a roan appearance. The head and legs retain the original base color tones. This coat is based on Bay.
Quando combinamos esses códigos genéticos, criamos uma matriz de probabilidades. É importante lembrar que o resultado visual (fenótipo) muitas vezes esconde genes recessivos que podem pular uma geração.
The Genotypes Involved
For a horse to have the coat Dun Smoky Black. it carries specific gene combinations. The possible genotypes for the sire include variants such as: E/e a/a Cr/n D/n, E/e a/a Cr/n D/D, E/E a/a Cr/n D/n, E/E a/a Cr/n D/D.
As for the dam, being Roan Bay, may present in its DNA the alleles: E/e A/a Rn/n, E/e A/a Rn/Rn, E/e A/A Rn/n, E/e A/A Rn/Rn, E/E A/a Rn/n, E/E A/a Rn/Rn, E/E A/A Rn/n, E/E A/A Rn/Rn.
Understanding the Alleles
To understand the result of this crossing, note the gene sets at play:
- E/ (Extension - Dominant): The Extension gene controls eumelanin (black) production. At least one E allele allows the horse to have black hairs.
- A/ (Agouti - Dominant): The Agouti gene controls black distribution. The A allele restricts black pigment to the points (mane, tail, legs).
- a/a (Non-Agouti - Recessive): Allows black pigment to spread uniformly across the body. Essential for Solid Black (if E/).
- Cr/n (Heterozygous Cream): One copy of the dilution allele. Lightens red pigment to gold (e.g. Palomino, Buckskin).
- D/ (Dun - Primitive Gene): Dilutes body color and adds dorsal stripe and leg barring.
- Rn/ (Roan - Rosilho): Mixes white hairs throughout the body, keeping head and extremities in the original color.
Calculated Probabilities
Being the sire Dun Smoky Black with genotype (E/e a/a Cr/n D/n), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (a) allele to 100% of offspring, allowing black to spread in homozygosis (if Extension is present) and has a 50% chance of transmitting the Cream dilution allele (Cr) and has a 50% chance of transmitting the primitive Dun allele (D).
Being the sire Dun Smoky Black with genotype (E/e a/a Cr/n D/D), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (a) allele to 100% of offspring, allowing black to spread in homozygosis (if Extension is present) and has a 50% chance of transmitting the Cream dilution allele (Cr) and always transmits the primitive Dun allele (D).
Being the sire Dun Smoky Black with genotype (E/E a/a Cr/n D/n), it transmits the (E) allele to 100% of offspring, enabling black pigment production (eumelanin) and transmits the (a) allele to 100% of offspring, allowing black to spread in homozygosis (if Extension is present) and has a 50% chance of transmitting the Cream dilution allele (Cr) and has a 50% chance of transmitting the primitive Dun allele (D).
Being the sire Dun Smoky Black with genotype (E/E a/a Cr/n D/D), it transmits the (E) allele to 100% of offspring, enabling black pigment production (eumelanin) and transmits the (a) allele to 100% of offspring, allowing black to spread in homozygosis (if Extension is present) and has a 50% chance of transmitting the Cream dilution allele (Cr) and always transmits the primitive Dun allele (D).
Being the dam Roan Bay with genotype (E/e A/a Rn/n), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (A) allele (restriction) to 50% and the (a) allele (no restriction) to the other 50% and has a 50% chance of transmitting the Roan allele (Rn).
Being the dam Roan Bay with genotype (E/e A/a Rn/Rn), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (A) allele (restriction) to 50% and the (a) allele (no restriction) to the other 50% and always transmits the Roan allele (Rn).
Being the dam Roan Bay with genotype (E/e A/A Rn/n), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (A) allele to 100% of offspring, restricting black pigment to the extremities and has a 50% chance of transmitting the Roan allele (Rn).
Being the dam Roan Bay with genotype (E/e A/A Rn/Rn), it transmits the (E) allele (black factor) to 50% and the (e) allele (red factor) to the other 50% and transmits the (A) allele to 100% of offspring, restricting black pigment to the extremities and always transmits the Roan allele (Rn).
Based on a standard scenario, the statistical chances for foals from this crossing are:
Roan Dun BuckskinOpen Coat ➜ 7,6%
Dun BuckskinOpen Coat ➜ 7,6%
Roan BuckskinOpen Coat ➜ 7,6%
BuckskinOpen Coat ➜ 7,6%
Roan Dun BayOpen Coat ➜ 6,8%
Dun BayOpen Coat ➜ 6,8%
Roan BayOpen Coat ➜ 6,8%
BayOpen Coat ➜ 6,8%
Roan Dun Smoky BlackOpen Coat ➜ 3,3%
Dun Smoky BlackOpen Coat ➜ 3,3%
Roan Smoky BlackOpen Coat ➜ 3,3%
Smoky BlackOpen Coat ➜ 3,3%
Roan Dun BlackOpen Coat ➜ 3,3%
GrulloOpen Coat ➜ 3,3%
Roan BlackOpen Coat ➜ 3,3%
BlackOpen Coat ➜ 3,3%
Roan Dun PalominoOpen Coat ➜ 1,6%
Dun PalominoOpen Coat ➜ 1,6%
Roan PalominoOpen Coat ➜ 1,6%
PalominoOpen Coat ➜ 1,6%
Roan Dun ChestnutOpen Coat ➜ 1,6%
Dun ChestnutOpen Coat ➜ 1,6%
Roan ChestnutOpen Coat ➜ 1,6%
ChestnutOpen Coat ➜ 1,6%
Roan Dun Dark BrownOpen Coat ➜ 0,8%
Dun Dark BrownOpen Coat ➜ 0,8%
Roan Dark BrownOpen Coat ➜ 0,8%
Dark BrownOpen Coat ➜ 0,8%
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