That's a good analogy. Humans don't have subraces in real life or in-game.
I don't know- if you really look, you can see all kinds of "subraces"* in humanity due to environmental pressures- the pygmy tribes, those whose lungs are more acclimated to mountain living (like in Peru or the Himalayas).
And though they're not more cold resistant than other humans, Inuits and other (far) North American indiginous peoples are less susceptible to the ills resulting from diets high in animal fats.
* in the game sense, because "races" don't have a real big basis in science