Chloe Dog

Inheriting Traits

 
Scientific Legacy

The LabraSpanTerriPherd

A mixed-breed dog’s heritage can vary in complexity from a simple first-generation cross of two breeds—say a Labrador and a Cocker Spaniel—to multiple breeds such as a Labrador, Cocker Spaniel, Rat Terrier and German Shepherd mix. Mixed-breed dogs can vary greatly in size, shape and color and can be hard to identify visually, as has been found in studies like the one done by Dr. Julie Levy at University of Florida. It can be difficult to identify all the breeds present in their genetic make-up just by looking at them. In fact, visual identification, even by professionals, is only accurate about 25% of the time!

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Tula

Example of a Simple Mixed-breed Dog

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Frankie

Example of a Complex Mixed-breed Dog

There's Really No Lab in There?

In a dog physical appearance is largely controlled by a small number of genes—only about 2%—so it’s important to understand dominant vs recessive genes. Recessive are those you need two copies of to inherit the trait and dominant you only need one. Traits such as a short black coat, block head shape, or drop ears might make you think of some of the more popular breeds with these same features. But dominant traits such as these, just by the very nature of being dominant, can be attributed to literally hundreds of breeds beyond the one you’re thinking of. Likewise a trait that is recessive such as a long coat, prick ears, or tan points that is associated with a specific breed, may not make it past the dominant ones and therefore can’t be seen.

 

 
Puppy Mix

Just Like Human Siblings

Looking around your own family you can probably see plenty of variation even among those most closely related to you such as your parents and/or siblings. It’s no different with dogs. Genetic Recombination is when chromosomes swap various pieces of DNA between them, resulting in the inheritance of a unique combination of DNA. This process happens in the passing down of genes from the parents, grandparents, and even great grandparents. On average, through the DNA of their parents, puppies are receiving about 25% of their total genetic makeup from each of their grandparents and approximately 12.5% from the great grandparents. Because of the random nature in which genes are passed down, siblings can sometimes have differences in the breeds identified (or placement of the breeds) in their family trees. The puppies here are a great example as they are all from the same mother. The black one on the left and the black and white one on the right have the same father. And yet, just like human siblings, they all have a unique look based on what they individually inherited from mom and dad.

 
 

Features of Mixed-breed Dogs

Mixed-breed dogs can be simple or complex. The more pure or mixed breeds in a dog’s ancestry, the more difficult it is to identify a dog’s pedigree.

The further back a given pedigree is in a dog’s history, the more mixed and diluted the characteristics in the genetic signature will be. Genetic signatures from purebred parents of a mixed-breed dog are easier to detect than grandparents, and both are much easier to detect than great-grandparents. A range of possible body shapes and sizes can be seen in the appearance of mixed-breed dogs. Here are some of the more commonly seen ones.

Fun Fact

Physical features of certain breeds such as the flattened face of the Bulldog, or the extremely curled tail of the Pug, seldom survive even the first cross-breeding.

 

Ear types

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Labrador_Retriever
German_Shepherd_Dog
Airedale_Terrier

Tail styles

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Labrador_Retriever
German_Shepherd_Dog
Airedale_Terrier

Muzzle shapes

Chow_Chow
Labrador_Retriever
German_Shepherd_Dog
Airedale_Terrier

Looks Can Be Deceiving

These three dogs all have at least 50% Golden Retriever in their ancestry; however, they all look very different, and none of them look like a purebred Golden. Depending on what dominant traits and/or recessive traits a dog receives from its parents, the way it expresses the different breeds in its ancestry can vary greatly.