I have added this page to address the topic of imported bloodlines! Chihuahua's have been imported to the US from all over the world over the past several years! A lot of the puppies are even advertised as "import lines" or "Russian lines". This was a huge sales tactic in the last few years. The imported lines had a slightly different look that many people fell head over heels in love with! They had a shorter muzzle, and big, bright eyes! I fell in love with the look as well! I imported 2 girls from Russia myself!
Here is a little back history though. Chihuahua's have an open fontanel and a very domed head. They are the only breed where an open fontanel, or molera, is acceptable and considered a trait of the breed! If you go to the AKC website and read through the description it is listed as a trait and accepted. Not considered a fault. HOWEVER, the rest of the world is under FCI (Federation Cynologique Internationale) regulations, not AKC. They are 1 of the only registries that are accepted by the AKC(American Kennel Club) and able to be transferred to AKC registration. FCI however changed their requirements several years back to require that NO chihuahua registered with them could have an open fontanel! Since its a trait that has been in the breed forever and is now required to be bred out dogs who already have this trait arent going to help eliminate it!
It was also discovered that some of these imported dogs were showing up with some traces of other breeds in them. There are several speculations and explanations. I assume that another breed was bred in to eliminate the open fontanel issue... Throughout history its known that another breed was used to add the longcoat gene into the chihuahua breed. They have not always had longcoat! When this was added in the pups were then bred back to a full chihuahua and after a few generations it was considered full chihuahua again! Even though another breed was clearly added in. This is how new traits show up in many different breeds!
Just a fun fact...Chihuahua's also used to have natural bobtails! This trait was bred out of the chihuahua's for the most part bc the very short bobtails also came with other issues that were not good. If the tail was too short it could affect the lower portion of the spine, as well as bowel and bladder function. So this trait was bred away from! However it is recessive and can occasionally still pop up!
So, Are Imports "mixed"? I would assume that those short muzzles were in fact bred in at some point while they were trying to also eliminate the open fontanel. However after several generations the pups are considered "pure" again. It is very common practice to line breed in other countries which I personally believe is why some of those breeds are still popping up on some of these breed tests. AKC has a statement on their website that the breed tests are not completely accurate as their are many other factors that play into the actual test. Some being where the base sample breeds are from geographically. AKC is going off of Pedigrees for registration and will not now or in the future consider the commercial breed tests for registration purposes as there are too many factors that can affect the exact results. (statement below)
I will be attaching below the links to both
Embark and AKC's explanation of these varying results and what it means in an imported dog or a pup from Imported Lines.
Regarding accuracy of genetic tests done by consumer available companies: https://www.akc.org/expert-advice/health/dog-dna-testing-genetic-screenings/
Will the new mixed-breed DNA test be employed in determining Conditional status?
"No. These new DNA tests are designed to determine the primary and secondary genetic heritage of mixed breed dogs, not to certify whether or not a dog is purebred. The AKC believes that the best way to determine parentage of a dog is still based on AKC’s long-standing DNA program and AKC does not intend to use these tests to evaluate a dog’s status as purebred. The AKC has long had procedures in place to deal with cases of impure breeding and will continue to use this method in dealing with any matters concerning the parentage of AKC registered dogs. AKC will, however, maintain positive contact with the laboratories offering breed identification testing, and may incorporate some of these techniques as a tool in registration inquiries in the future." AKC Website