Canine DNA Basics

Some useful information on the truth of canine genetic testing

I would like to start this page by saying this is MY OWN research and hard work.  I will, on this page, reference some information also available on the DDC Veterinary website.  Midwest Chihuahuas do regular genetic testing to determine breed purity, genetic identity, coat length information and in rarer cases, other available testing.  Information on that is included below.

The American Kennel Club uses MMI Genomics for DNA Profiling. A DNA profile is used for ID purposes only. Each animal has a unique DNA makeup and your genetics testing company uses a panel of markers for identifying the specific set of allele sizes that make your animal unique. This provides an accurate method to prove ownership and solve questions regarding parentage. For example, a DNA profile from an individual can be compared to DNA profiles of its "alleged" parents to determine whether they are truly the biological parents. A DNA profile will not determine the breed make-up or verify breed purity.   Let me say that again another way...DNA profiling can determine parentage and genetic identity but NOT the breed. 

Midwest Chihuahuas use DDC Veterinary for our genetics testing and use a lovely lab in the Czech Republic for advanced testing for our parents.  They can be found on the web at and are the same company as the DDC which does human DNA testing for the government as well as shows like "Maury" for determining parental lines.  This is the Veterinary division of this large and well-respected company.  We use DDC Veterinary because they do all testing in-house and offer many other breed specific tests aside from simply knowing if your dog is purebred or not. 

One of the tests we have run is a Mixed breed ancestry test.  You can get this from DDC Veterinary ( or The Wisdom Panel (  The Wisdom panel will test for more breed types than DDC Veterinary.  This testing will show all breed types in your dog.  If it only comes back Chihuahua then you know that.  We also recommend DNA profiling.  This is what AKC requires (all they require) and if you are unsure on the parentage of the puppy you can test two parents and a puppy for $114.00 (at the time of this writing) through DDC Vet.  Or simply $38.00 for single DNA profile. 

When we had a future Momma who is a smooth coat with two smooth coated parents (like Zojja) we test for the Coat Length Determination DNA test.  The smooth coat gene is DOMINANT (indicated by capital letters) and the long coat gene is recessive (indicated by lower case letters).  DNA marker tested – FGF5 shows how Long-haired coat length is inherited as an autosomal recessive trait. Therefore, dogs that are carriers of the long-hair mutation will appear to be normal (short hair) themselves, but will likely pass on the long-hair allele 50% of the time.  If your smooth coat Chihuahua does not carry the long coat gene it will not produce long coat puppies even when bred to a long coated partner.  We tested Zojja in 2013 for breed purity, DNA profile, and coat length, color loci color verification to find out if when bred to one of our LC males here in 2013 if she will have split litters (some long coat some smooth coat) or all smooth coat. Zojja DOES NOT carry the gene and produces smooth coats regardless of litters sire.


Midwest Chihuahuas DNA tests males and females.  We only test for coat length if we do not know of long coats in the recent history of the female.  All our long coat males are double long coat.

Chihuahua specific testing offered by DDC Veterinary include:

  1. Color E-Locus DNA Test
  2. Color B-Locus DNA Test
  3. Coat Color K-Locus DNA Test
  4. Coat Color DNA for Fawn/Sable
  5. Coat Color DNA for Recessive Black
  6. Coat Color DNA for Black Mask
  7. Coat Length Determination DNA Test
  8. Degenerative Myelopathy DNA Test
  9. Uric Acid DNA Test (Hyperuricosuria)

DDC Veterinary offers multi-test discounts

The bottom line is you can learn a lot from a little testing.  Look at our retired Mom, MooMoo, she is beautiful and neither of her parents have a black mask and they are smooth coat.  However, MooMoo carries both the long coat allele and the black mask one and has produced long coats (actually when bred to our long coat males, more than 50% long coat) and two pups who matured with black masks.  Remember, DNA and Genetics should be fun!

© Working Dog Chihuahuas by Midwest, 2007