We have documented several instances where registered Yorkshire Terriers have shared ancestry with Biewer Terriers. This is more likely to be the case in Yorkshire Terriers who are parti or have parti ancestors - “Parti” refers to the white spotting commonly seen in Biewer Terriers. This is likely due to shared ancestry between the first AKC registered parti Yorkshire Terriers and the founding dogs that contributed to establishing the Biewer Terrier as a separate breed.
You should know that a genetic ancestry report will not impact registration status! Purebred status is defined by pedigrees at registration bodies and does not require DNA testing to prove ancestry. Typically, the breed registration requires that offspring are produced by two registered parents. As genetic ancestry and purebred status are two different, completely separate things, it’s not uncommon for a registered purebred dog to have a genetic ancestry test report a breed other than what’s on their pedigree.
To learn more about why it is common to see registered purebred dogs with genetic ancestry that does not align with their registration status, click here!