How is coat color inherited in dogs? - briefly
Coat color inheritance in dogs is primarily determined by two types of genes: those that code for pigment production and those that control how the pigments are distributed on the fur. The most significant gene influencing coat color is the Melanocortin 1 Receptor (MC1R) gene, which regulates the type and amount of melanin produced, resulting in various shades and patterns.
How is coat color inherited in dogs? - in detail
Coat color inheritance in dogs is a complex process governed by several genes, with each gene contributing specific traits to the overall appearance of the dog's fur. The most influential genes are located on different chromosomes and interact with one another to determine the final coat color.
One of the primary genes involved in coat color inheritance is the Agouti signaling protein (ASIP) gene, also known as the A-locus. This gene is responsible for the distribution of eumelanin (black or brown pigment) and phaeomelanin (red or yellow pigment) on the dog's coat. The A-locus has three main alleles: A (dominant), at (recessive), and a (recessive). The A allele allows for the expression of both eumelanin and phaeomelanin, resulting in agouti or grizzled patterns. The at allele restricts eumelanin to the tips of the hairs, leading to tan points on a solid background. The a allele prevents the expression of eumelanin entirely, resulting in a solid red or yellow coat.
Another crucial gene is the Melanocortin 1 Receptor (MC1R) gene, also known as the E-locus. This gene determines the type of pigment produced: either eumelanin (black or brown) or phaeomelanin (red or yellow). The E-locus has two main alleles: E (dominant) and e (recessive). The E allele allows for the production of both eumelanin and phaeomelanin, while the e allele restricts pigment production to phaeomelanin only.
The Tyrosinase (TYRP1) gene, also known as the B-locus, plays a significant role in the dilution of coat color. This gene has two main alleles: B (dominant) and b (recessive). The B allele allows for full expression of eumelanin, resulting in a solid black or brown coat. The b allele causes partial dilution of eumelanin, leading to shades of gray, blue, or liver.
Additionally, the KIT ligand (KITLG) gene, also known as the C-locus, influences the intensity and distribution of coat color. This gene has two main alleles: C (dominant) and c (recessive). The C allele allows for full expression of eumelanin and phaeomelanin, resulting in a darker coat with distinct markings. The c allele causes partial dilution of pigment, leading to a lighter coat with less distinct markings.
It is essential to note that the interaction between these genes is not always straightforward, as they can exhibit incomplete dominance or codominance. For instance, the K-locus, which determines the presence or absence of a black mask on the dog's face, interacts with the A-locus to produce various patterns and shades.
In conclusion, coat color inheritance in dogs is a multifaceted process governed by several genes, each contributing unique traits to the final appearance of the fur. The interaction between these genes gives rise to the vast array of coat colors and patterns observed in the canine world.