Funny story. I was listening to an interview with Chinese historian Carl Zha. According to Zha the CIA ran a breeding program for mules in the 1980s for use in Afghanistan to supply the mujahadeen. The breeding program was in Tennessee and used Tennessee mules. All the mules died after about a year because for whatever reason they couldn't deal with the conditions in Afghanistan. So the CIA went looking for a mule provider in the region and ended up sourcing mules from Uyghur tribesmen in western China. These mules didn't die. And thus began the CIA's relationship with the Uyghur.

I'm not vouching for the authenticity of this story, but it is a good story none the less.