all North American bison carry some regions of domestic cattle DNA
Researchers at Texas A&M University report that today’s North American bison carry the genetic fingerprints of domestic cattle. Essentially, these once wild beasts were brought back from the brink of extinction in the late 1800s through partial hybridization with cattle.
The beasts carry several small but clearly identifiable DNA regions from domestic cattle, according to a new study.
“Today, it appears that all major bison herds in public, private, tribal and non-governmental organizations have low levels of bovine genomic introgression,” said Sam Stroupe, Ph.D. student at Texas A&M and first author of the study. “This includes Yellowstone National Park, as well as Elk Island National Park in Canada, which were considered free of livestock introgression based on previous genetic studies.”
“This comparative study makes it clear that the people responsible for saving bison from extinction in the late 1800s are also responsible for introducing bovine genetics to this species,” said co-lead researcher James Derr.
A new study published in the journal Scientific Reports has found the strongest evidence to date that all North American bison carry several small, but clearly identifiable, regions of DNA from domestic cattle.
The study builds on previous work done by Derr’s team, which suggested that only a few wild bison herds in North America lack domestic cattle genes. As the technology improved since the last study, the team was curious to double-check their findings – and discovered that even those few herds were, in fact, also hybrids.
However, the results are not all bad. The team explains that conservation efforts could actually benefit from the results, as wild bison herds have historically been isolated to prevent accidental hybridization with livestock; since this goal is no longer possible, it will give conservationists much more flexibility in how and where they can work with bison.
The common ancestry identified in the study is the product of multiple hybridization events between North American bison and cattle over the past 200 years, the researchers report. After the bison population collapsed in the 1800s, America was left with a shortage of beef. Local farmers attempted to cross-breed domestic cattle and bison to create a new breed that would grow bigger and produce more meat. Such a hybrid was produced, but without the expected increase in muscle mass, so cross-breeding efforts were largely abandoned. Yet this has resulted in a number of artificial hybrids.
As the United States realized that bison were on the verge of extinction, a nationwide effort began to try to preserve existing populations while helping the species recover. However, virtually the only animals available to establish conservation herds were the hybrids developed earlier.
“As a result, these well-intentioned hybridization efforts leave a complicated genetic legacy,” Davis said. “Without these private herds, the bison may have become extinct. At the same time, this intentional introduction of cross-species DNA has resulted in the presence of residual imprints of cattle in the genomes of the entire contemporary species. “We now have the computational and molecular tools to compare bison genomic sequences to thousands of cattle and conclusively determine the level and distribution of domestic cattle genetics in bison that represent each of these historic bison lineages.” .
The results should inform conservation efforts in the future and, according to the team, give us context to better understand these animals, their history and their place in nature and in our economies. Importantly, the team adds, that although hybridizations occur naturally, bison history was a deliberate, man-made event closely tied to the near extinction of bison due to hunting. commercial.
An important consequence of these findings is that conservationists and bison ranches can now adapt new strategies to better promote and maintain the animals’ genetic diversity, improve the overall health of the species, and ensure its continued survival.
The article “Genomic evaluation of hybridization in historic and modern North American Bison (Bison bison)” was published in the journal Scientific reports.