Genetic Health

Photo by H Dragon used under a Creative Commons License

There is controversy brewing between environmentalists and cattle ranchers in Wyoming as plan to cull the Yellowstone Bison herd are put on hold.  Original plans were to cull all bison who test positive for brucellosis, but new data suggests this may cause irreparable damage to the genetic health of the herd.

But the study from Thomas Pringle, a biochemist on the genomic team for the University of California at Santa Cruz, faulted the government as overlooking a hereditary weakness in the bison herd that could be amplified by the culling program.

He found that most Yellowstone bison whose DNA were tested carried a genetic mutation that affects cellular metabolism and makes bison lethargic, rendering them less capable of foraging in deep snow, fending off predators and competing for mates.

Pringle, whose work on other genomes has appeared in professional journals such as Science and Nature, said his bison research demonstrates that culling of the wild herd based on brucellosis, rather on the health of their genes, may push the species over the edge into a form of extinction.

"They're taking a really high risk of killing bison with healthy genes and getting into a situation where they can't go back; the good DNA will be lost," said Pringle, whose paper relies on published genetic data, analyses of bison fossils and samples from herds at national parks like Yellowstone.

Genetic analysis has already become a powerful tool in managing captive populations.  Zoos regularly use basic genetic analysis in choosing mating pairs to maximize genetic diversity.  This method is based on pedigree analysis and is slowly moving towards a true genetic analysis.  However, it is time to use genetic tools to manage wild populations.  Whatever the outcome in this particular case, it is encouraging that newer science is getting a foothold in wildlife management.