NORTH AMERICAN BISON GENETIC DIVERSITY

BISON HERD GENETIC DIVERSITY

All Content Sourced from GENETICALLY PURE AMERICAN BISON: HOW MANY ARE LEFT? | Conservation Genetics and North American Bison (Bison bison)

The Yellowstone herd of American Bison are an iconic animal for the American ecosystem as a whole. Weighing up to 2,000 pounds on a diet consisting only of naturally forged grass, their herds number into the hundreds. The Yellowstone Bison herds are unique, seeing as they have never been interbred with domestic cattle.

This is important as the genetic diversity of the Great American Bison remains at risk of extinction. In 2019, it was discovered that wild North American Bison is in fact shedding their genetic diversity, leading their future herds to follow into a weakened resilience against disease and unpredictable climate events or changes. Genetic Diversity is vital as it helps maintain the overall health of the bison population. Not just in bison herds, genetic diversity in bison herds can also help plants and animals resist diseases, shrug off pests, and handle other stressors. Diversity provides a population with a buffer against climate change and gives it the ability to adapt to new environments.

Texas A&M University conducted DNA testing on more than 30,000 bison in both private and public herds across North America. They were able to conclude that about 6% of those bison tested have shown evidence of cattle DNA. The level of cattle genetics in those bison averaged less than 1.5% of their genetic make-up. Overall, it is said that there are now about 11,000 genetically pure bison left in North America. These bison are sparsely segregated amongst small, isolated herds, most of them numbering fewer than 100 animals. Thus, leaving them prone to inbreeding and genetic drift.

The genetically pure North American Yellowstone bison herd is said to have descended from the Goodnight Herd (Texas) which was populated by 5 founders: The Alloway-McKay Herd (Canada), The Dupree-Phillip Herd (South Dakota), The Jones Herd (Kansas and Oklahoma), the New York Zoological Gardens private herd, and The Pablo-Allowed Herd.

The DNA purity of the North American Bison genetics was later defined by Wilson Strobeck in 1999. After he examined genetic variation in a number of herds, he correlated their genetic variations with their founder number, and their corresponding number of founder sources in order to find a positive correlation between the number of founders and the average number of alleles. Concluding a variation of genetics at 11 total microsatellite loci in the following herds (all deemed genetically pure & diverse):