[hcarvalhoalves]

> There's a subgroup of Asians spanning the Himalayas and east Asia that have blue bottommed babies

That's funny. I had to Google it because I never heard about that before, but apparently it's extremely common!

According to Wikipedia this trait is common not only on asians but also native americans, so it predates Genghis Khan.

[1] http://en.wikipedia.org/wiki/Mongolian_spot#Prevalence

[kinleyd]

That makes sense actually, given the belief that native Americans came from central Asia before the ice melted on the Bering Straits. When you compare native Americans with Asians from around the Himalayan region, the features are strikingly similar. I wonder if native Americans also have the high altitude gene at the same level of probability as Tibetans, given their shared blue bottoms? :)

[hcarvalhoalves]

Possibly. Look at the Inca Empire. Peru, Bolivia, Chile are all above sea level. Machu Picchu peak is at 2.5km.