[Cronos]

I do know that as recent as 2,000 years ago, all the people to the north and east of the Gogi Desert were Caucasians

These were the Yueh-something known as the Kushans. They were an Aryan group that moved out of western-Indian/Persia and split from the group that headed west into Europe. When the Chinese Empire expanded, these were forced (indirectly by the Turkic Huns) to the South (they formed the Kushan dynasty in India in the centuries aroudn the birth of Christ) and WEst (Slavics?)

[blam]

"These were the Yueh-something known as the Kushans. "

Those were the Yuezhi. There were two groups, the Greater and Lesser Yuezhi. The Greater Yuezhi formed an alliance with the Han and the Lesser Yuezhi were forced back to the northeast. It was not until around 100-200BC that any 'Asian' skeletons began to show up anywhere east of the Jade Gate of the Great Wall of China at Dunhuang.

Then there were the fiercest fighters of all, the Xiongnu who prompted the building of The Great Wall. I believe the Xiongnu were related to the Schythians.