Beefalo Genetic Ancestry Study Reveals Surprising Lack of Bison DNA

A study published June 10 in eLife found that most Beefalo, a bison-cattle hybrid breed, lack detectable bison DNA, challenging claims about their genetic makeup. Researchers analyzed preserved semen samples from 47 animals, most dating to the 1970s and 1980s, and found 39 contained no bison ancestry, with the remaining 8 having less than the 3/8 bison DNA standard set by the American Beefalo Association (ABA).

Study Details and Surprising Findings

Beth Shapiro, an evolutionary biologist at the University of California, Santa Cruz, noted the results were unexpected. “It was a surprise to us to discover that most of the Beefalo individuals we sequenced did not have detectable bison ancestry,” she said. The research team focused on the breed’s founding individuals rather than modern cattle, as few contemporary samples were available.

The ABA disputes the findings, stating that all “full-blood” Beefalo in its registry must pass DNA tests through labs at the University of California, Davis, and Neogen Genomics. Dan Stricker argued the study’s samples did not represent “modern, registered Beefalo that have been selectively bred for bison traits over many generations.”

Implications for Hybrid Breeding

The study suggests that creating stable bison-cattle hybrids is biologically challenging. Throughout the 1900s, attempts to establish such hybrids repeatedly failed, including Beefalo. Jonas Oppenheimer, a co-author and evolutionary biologist at the Centre for Paleogenetics, stated it is unlikely modern Beefalo have more bison DNA than the founding animals.

While Beefalo may lack bison ancestry, wild bison populations have shown some cattle genetic influence. Conservationists worry this could impact bison behaviors, disease resistance, and legal protections. However, Shapiro emphasized that gene flow between the species has been “far less frequent and far less consequential than previously believed.”

Conservation and Genetic Research Context

The findings add to ongoing debates about hybridization in wildlife. The study underscores the complexity of hybrid breeding programs, which often face biological hurdles.

Shapiro’s work on cattle-bison hybrids, including this study, highlights the need for rigorous genetic testing in breeding initiatives.

What This Means for Beefalo Breeders and Consumers

While the ABA maintains its standards, the research suggests that the genetic foundation of the breed may not align with its promotional claims.

For now, the ABA continues to enforce DNA testing requirements, asserting that registered Beefalo meet their genetic criteria.