Genetics

The Biewer Terrier Genetic Study That Created a New Breed

The Biewer Terrier became the first AKC breed recognized primarily on genetic evidence rather than appearance. Here's the landmark 2007 UC Davis study that made it happen.

June 20, 2024 · 5 min read

The Origin Story

On January 20, 1984, Werner and Gertrud Biewer's Yorkshire Terrier — Fru Fru von Friedheck — gave birth to a parti-colored puppy: blue, gold, and white. Werner Biewer, fascinated by this color, began specifically breeding for the tri-color parti pattern. By the mid-1980s, the 'Biewer Yorkshire Terrier à la Pom Pon' was being shown in Germany, and a small dedicated breeding community developed around the type.

The 2007 UC Davis Study

When Biewer breeders sought recognition in the US, the question arose: is the Biewer a color variation of the Yorkshire Terrier, or a distinct breed? To answer this, a team at the University of California, Davis — led by Dr. Niels Pedersen — conducted a DNA population study. Using genetic markers across the genome, they compared Biewer Terrier dogs against Yorkshire Terrier dogs. The result: Biewer Terriers showed a statistically distinct genetic profile from Yorkies — different enough to support classification as a separate breed.

What Made This Historic

The Biewer Terrier became the first dog breed in history to be recognized primarily on the basis of genetic science rather than phenotypic (appearance) standards alone. The AKC formally recognized the Biewer Terrier as a full breed in January 2021. The study set a precedent for how genetic evidence can and should inform breed classification — a model that may influence future breed recognition decisions.