- American bison nearly went extinct in the 1870s, with a population dropping to about 500, but conservation efforts have helped them rebound to around 500,000.
- A recent study found that all tested American bison contain low but significant amounts of domestic cattle DNA, ranging from 0.5% to 2.5% of their genome.
- Cattle DNA entered bison populations through past hybridization, often encouraged by ranchers who saved bison from extinction in the late 1800s.
- Scientists believe no major bison herds are completely free of cattle genes, but this may not harm the species, as hybridization is a natural part of evolution.
- The presence of cattle DNA could boost bison genetic diversity, and conservation efforts should focus on ecological function rather than genetic purity.