New Genetic Study Illuminates Bison Evolution and Conservation

Researchers from more than 30 institutions sequenced 115 ancient and 45 modern bison genomes to trace the species’ history over the past 20,000 years. The analysis, published in *Science*, shows that before the 19th-century collapse bison across North America were genetically connected, with extensive gene flow and few regional distinctions. A 10,000-year time transect built from 27 Wyoming bison remains—including 16 specimens from five archaeological sites—was pivotal in establishing this pan-continental connectivity.

Bozeman Daily Chronicle[Science Through Covers] UC Berkeley team reveals how 500 surviving North American bison preserved genetic diversity

Bison once numbered roughly 50 million across the continent. Large-scale hunting by European-descended settlers in the 1800s drove the population to a nadir of about 500 wild individuals by 1890. Conservation actions by individuals, tribes, and governments later restored the species to an estimated 530 000 animals today, comprising both managed herds and free-ranging groups such as those in Grand Teton, Yellowstone, and Canada’s Wood Buffalo National Park.

[Science Through Covers] UC Berkeley team reveals how 500 surviving North American bison preserved genetic diversity

The study confirms that ancient bison exhibited minimal genetic differentiation, making it difficult to assign a specimen to a specific region based solely on DNA. This extensive historic gene flow preserved genetic diversity even after the severe 19th-century bottleneck; the surviving ~500 bison retained a substantial portion of the species’ variation.

[Science Through Covers] UC Berkeley team reveals how 500 surviving North American bison preserved genetic diversity Bozeman Daily Chronicle

Contrary to recent assertions that nearly all modern bison carry cattle DNA from historic hybridization experiments, the researchers detected cattle ancestry in only 32 of 97 modern plains-bison samples. The limited presence suggests that cattle genes could be eliminated over time through genetic drift, provided that inter-herd gene flow remains sufficient to prevent fixation of cattle segments.

Bozeman Daily Chronicle[Science Through Covers] UC Berkeley team reveals how 500 surviving North American bison preserved genetic diversity

The authors argue that future bison recovery depends on management strategies informed by this deep-time genetic insight. Restoring bison as keystone members of the Great Plains ecosystem will require maintaining or enhancing gene flow among isolated herds to prevent the persistence of undesirable cattle alleles and to sustain overall genetic health.

Bozeman Daily Chronicle

State Archaeologist Spencer Pelton highlighted the study’s breadth, noting that the extensive use of UW’s archaeological repository underscores the value of university collections for large-scale genetic research.

Bozeman Daily Chronicle

• “This study provides, perhaps, the most comprehensive assessment of North American bison and how they’ve changed over the past 20,000 years, and it’s noteworthy that so much of the genetic material used in the study comes directly out of UW’s archaeological repository,” — State Archaeologist Spencer Pelton, at UW — appears today in the journal Science

Bozeman Daily Chronicle

Earlier analyses had suggested that virtually all modern bison possess some cattle ancestry. The new findings, however, reveal cattle genes in a minority of sampled individuals, directly challenging those prior conclusions. No additional independent studies are cited that either corroborate or dispute this revised estimate, leaving a gap in broader verification of cattle-gene prevalence across the continent’s bison populations.

Bozeman Daily Chronicle