The white buffalo

OK, this was local news here, and now it's national news:

MILWAUKEE - A farm in Wisconsin is quickly becoming hallowed ground again for American Indians with the birth of its third white buffalo, an animal considered sacred by many tribes for its potential to bring good fortune and peace.

This is much, much better than panda news. No question.

Still, I have to think they are missing an opportunity here to make this a bit, well, educational:

Dave Heider said he was inspecting damage on his farm after a late August storm when he saw the newly born buffalo, a male. His last white buffalo, a female named Miracle, died in 2004 at the age of 10. Thousands of people came to see the animal, whose coat became darker as it aged.
...
[The new calf] is no relation to Miracle, he said.
"We never even thought about having another white one until we got this one," he said. "There's got to be a reason that we're getting these white calves."

Yes. The reason is called inbreeding. Remember that a hundred years ago, there were only around 500 bison in North America? Considering that the "white" pelage here is not really pigmentless -- and becomes darker through ontogeny -- this may well not be a simple Mendelian trait. But even if it were, very nearly all the bison in this herd must be close relatives!

And there's another reason for white coloration --- the majority of today's bison have cattle genes introduced during the last century. Some of these genes influence coat color. Hence, color variation in today's bison includes a range that historical bison never would have had, because of genetic introgression from cattle.

No, the story doesn't go into this sort of thing. It does quote an expert, though:

Odds of having a white buffalo are at least 1 in the millions, said Jim Matheson, assistant director of the National Bison Association. For years buffalo in general were rare but their numbers are increasing, with some 250,000 now in the U.S., he said.

OK, first of all, the entire population of bison in North America is now on the order of 500,000. Considering there have been three white bison at this one farm we know that the odds are not "1 in the millions"!

In fact, white bison are bred at one ranch in Arizona, and a record of at least a dozen of them exist from there and other places. Now, I know that the AP can't be bothered to consult Wikipedia for this sort of thing, but this seems like an especially good chance to dispel some myths about genetics -- and this one connects very clearly to the problems of endangered species in small populations!