Genotype vs Phenotype: The Difference, With Dog Examples
Genotype is the set of gene versions a dog carries; phenotype is what you can see. Here's how the two connect, using dog coats as examples, and why a dog's DNA doesn't always match its looks.
By PuppyGenes · How we research and write our guides
A dog's genotype is the set of gene versions it carries, usually written as two letters for each gene, one from each parent. Its phenotype is what you can see or measure: a curly coat, a beard, its adult size. Genotype shapes phenotype, but the two don't always match one to one, because some versions stay hidden and many traits depend on several genes and the environment.
The short version
- Genotype: the versions of a gene, called alleles, that a dog carries.
- Phenotype: the trait you can see or measure, such as a long coat or a beard.
- Same look, different genotypes: a furnished dog can carry one or two copies of the furnishings variant.
- Hidden versions: a dog can carry a recessive variant it doesn't show, and pass it on.
- The environment matters too, especially for size, weight and behaviour.
A dog example: furnishings
Furnishings, the beard, moustache and eyebrows of Schnauzers, Poodles and most doodles, come from an insertion in a gene called RSPO2. A study of more than 1,000 dogs from 80 breeds found that 297 of 298 furnished dogs carried at least one copy of the insertion. One copy is enough, so two different genotypes give the same phenotype:
| Genotype | What the dog looks like |
|---|---|
| Two copies of the furnishings variant | Furnished |
| One copy | Furnished |
| No copies | No beard or eyebrows, called an improper coat in doodles |
The two furnished dogs look alike but differ for breeding: a dog with two copies can only pass on the furnishings variant, while a dog with one copy passes it to about half its puppies. Our guides to furnishings and improper coats explain what that means for a litter.
When genotype and phenotype don't line up
- Recessive versions hide. A short-coated dog can carry one long-hair version of FGF5 without showing it, as our long coat guide explains.
- Some versions have a partial effect. One copy of the KRT71 curl variant usually gives a wavy coat, and two copies a curly one.
- One gene can mask another. Two copies of the e variant of MC1R limit a dog to red and yellow pigment, whatever its other colour genes carry, as our coat colour hub shows.
- Many genes can share a trait. Size and behaviour are polygenic, shaped by many genes with small effects.
- The environment plays a part. Food, exercise, grooming and age all change how a dog looks.
Genotype and phenotype in a DNA report
A DNA report reads a dog's genotypes and predicts its phenotypes. The PuppyGenes physical appearance section predicts traits such as coat length, curl and furnishings from the related genes, each with its own confidence. In our public example reports, both Juno and Marley are predicted to be "likely furnished (moustache, beard and/or eyebrows)". If a prediction doesn't match your dog, the dog in front of you is the better guide, and our guide to DNA results that don't match looks explains why it happens.
Frequently asked questions
- What is the difference between genotype and phenotype?
- Genotype is the set of gene versions a dog carries; phenotype is the trait you can see or measure. A dog with two copies of a long-hair FGF5 variant (its genotype) usually grows a long coat (its phenotype).
- Can two dogs with the same phenotype have different genotypes?
- Yes. A furnished dog can carry one or two copies of the furnishings variant, because one copy is enough to show. The difference shows up in their puppies.
- Is coat colour a genotype or a phenotype?
- The colour you see is the phenotype. The versions of the colour genes behind it, such as MC1R, ASIP and TYRP1, make up the genotype.
- Can a DNA test tell what my dog will look like?
- It can predict some traits from genotypes, but a prediction isn't a guarantee. Hidden versions, other genes, the environment and low-confidence results all mean the dog in front of you has the final word.
From general to personal
See how this applies to your dog specifically.
Our at-home Complete Dog DNA Test adds your dog's own results to these tips across six report sections: breed ancestry, coat colour, physical appearance, temperament and size predictions, genetic diversity and oral microbiome. The report does not include genetic disease or health screening.