Mutations that are good for living in cold weather are probably bad for living in hot weather.
You don't want your body fat turning itself directly into heat if it's hot outside anyway.
But if you're living in Siberia you don't really have to worry about hot weather.
No quite true. Siberia during ice age and Siberia today are two different climatic patterns. Nowadays it is not unheard of to experience up to 40C during spring/summer. So people fit to withstand cold are going to suffer during heat waves.
Go ahead, cross that Rubicon - it won't hurt - much.
You won't con me with rubies.
Then perhaps rubles will do? Come along, comrade, there is much to be done!
Their high end MIGS were made of wood.
Aside from WW2 planes and earlier, which of the high end MIGs were made of wood?
Kir Bulichov, just like many other Russian sci-fi writers, are pretty much unknown to the West. He is excellent.
Another obscure, but brilliant Russian sci-fi writer is Sever Gansovski - with short stories like "Poligon", "Day of Fury", etc.: http://tinyurl.com/c6eygs4 , see also: http://www.isfdb.org/cgi-bin/ea.cgi?11119