Saturday, March 26, 2011

Genetic future of bison

I've spent the last few days in Tulsa at a conference sponsored by the American Bison Society, which is part of the Wildlife Conservation Society. The conference was attended by a mix of scientists, government officials, ranchers, and tribal members. The conference centered around three panels, two of which focused on the genetics of bison. The third panel, which I helped put together, was on the ecology of the bison. We were largely intermission for genetic questions.

A quick bit of history. Bison once ranged in the millions in North America, but at the end of the 1800's had been reduced to about a thousand animals. Some of the remaining bison had been bred with cattle in an attempt to improve the performance of cattle and cattle DNA became part of collective genome of bison. It is not evenly distributed among modern bison--some lineages have more than others, some appear to have none. The presence of cattle DNA in bison has largely consumed discussion on bison for the past decade. How much is there? How is it distributed? Does it have functional significance? Can we get rid of it and repopulate our herds with "pure" bison?

The discussion on the topics were long, nuanced, and technological at times--lots of next generation sequencing and single nucleotide polymorphisms being discussed. ABS will draft official statements, but for me, I think the meeting will be known as a watershed in tolerance and understanding for the modern American Bison. In short, most bison in public herds have some cattle DNA. Quantitatively, less than 1% of the nuclear DNA might be from cattle, but it's there. It possibly could be culled out of the herd, but the bison DNA that we would lose would far outweigh the potential benefit of removing traces of cattle ancestry. Bison also aren't unique. Many of our remaining wild species have DNA from other "species" in them. Wolves, bactrian camels, Przewalski's horses all bear the genetic imprint of domesticated relatives. 

We'll see what the official statements say, but American bison will always be a symbol of America's past. Yet, our bison are also a modern symbol--a bit mixed up, bearing the traces of past pain and hope and ambition, but one that probably should not be atomized any more. In some small way, the conference reflected a modern and sophisticated sense of tolerance.

So, when people visit bison in our parks and preserves, they are likely to be seeing a little bit of Hereford. But, it's a small price to pay if it reminds us to learn more about the animal's history. Much of the bison community seems willing to accept the mark of history and focus anew on continuing to restore  them.

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