New bison genome maps genetic traits, including albinism

Scientists from the Texas A&M School of Veterinary Medicine & Biomedical Sciences has recently achieved a significant milestone in the realm of genomics. Leading the research, Dr. James Derr and his team have developed the most comprehensive genome to date for the North American bison, utilizing cutting-edge genome sequencing technology. This advancement not only brings the bison’s genetic roadmap up to date but also unravels the genetic basis of albinism in these iconic creatures.

Albinism, a rare condition characterized by a lack of pigment, holds historical and cultural significance, as albino bison have been revered as a religious symbol by certain Native American Indigenous tribes. The study, detailed in a recent publication in G3: Genes, Genomes, Genetics, goes beyond merely updating the genetic information of bison; it establishes a framework for identifying genetic variations that impact crucial bison traits related to health and production value.

Dr. James Derr, a professor of veterinary pathobiology and genetics, previously led the team that created the first bison genome in 2015. Now, assembling a team including assistant professor of genetics Dr. Brian Davis, graduate student Sam Stroupe, and collaborators from Texas Parks and Wildlife and the National Park Service, Dr. Derr has spearheaded the development of this new reference genome.

The groundbreaking approach involved using advanced genome sequencing technology to create a high-resolution reference genome based on DNA from hybrids. Specifically, the researchers utilized DNA from a type of bison-cow hybrid known as an F1, characterized by a perfect 50-50 split between its parents’ DNA. F1 hybrids between bison and cattle, while historically rare, were identified in most bison herds in North America in a discovery made by Derr and his research partners last year.

The serendipitous discovery of an F1 hybrid was a pivotal moment for the research team. Sequencing the genomes of the F1 hybrid, the bison mother, and the domestic cattle father allowed researchers to separate bison DNA from cattle DNA regions. Leveraging the advanced cattle genome as a reference, the team successfully crafted the complete high-resolution reference bison genome.

Beyond the scientific achievement of updating the bison genome, the researchers applied their new genomic tool to delve into the genetic basis of albinism in bison. This endeavor led to a groundbreaking discovery—the identification of the gene mutation responsible for albinism. This marks the first time researchers have successfully determined the gene mutation responsible for an observable trait in bison.

Sam Stroupe, a graduate student on the team, explained the significance of their findings regarding albinism: “We knew albinism was an inherited recessive trait, but we didn’t know which gene was responsible. So, we sequenced the DNA from a few albino bison and compared them to those of normal coloration to find the mutation that causes albinism. As it turns out, the mutation causes an important enzyme to cease functioning correctly, which leads to the lack of skin pigmentation.”

The uniqueness of albino bison

White bison hold profound spiritual significance for many North American Indigenous peoples, symbolizing sacred entities with prophetic connections. The birth of a white bison, although not always indicative of albinism, is a cause for celebration within certain communities.

Despite the cultural reverence for these majestic creatures, Dr. James Derr, the lead researcher behind the comprehensive bison genome, cautions against attempting to selectively breed albino bison using genetic testing. He highlights a somber reality, stating, “Sadly, albino bison are often not very healthy. They tend to develop skin cancers, and they can develop other health problems as they age.”

Distinguishing albino bison from those resulting from crossbreeding with white cattle, particularly Charolais, is crucial. The latter lack the red eyes and pink nose characteristic of true albinos.

With the establishment of a more precise bison genome, scientists gain a valuable tool to delve into the genetic makeup of North America’s bison population. Dr. Derr emphasizes the significance of this development, stating, “The development of this new reference genome and the identification of a causative genetic mutation is exciting news for bison. It opens the doors for new discoveries and insights into bison genetics.”

This breakthrough is not only a scientific achievement but also a crucial step towards the future conservation management of the United States’ national mammal. As researchers unlock the mysteries within the bison’s genetic code, the potential for further revelations and informed conservation practices becomes increasingly promising.

Source: Texas A&M University

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