>>214324802
Humans are no different than dog breeds. All distinct human races trace their ancestry to a single specimen.
Like the sphynx cat. One single cat was born hairless so the owner bred the cat and kept the hairless ones until you have an entire population of hairless cats.
All blue eyed people trace their ancestry to one person.
Icelandic people sometimes look asian because many of them are Finnish, and Finnish people look like that because a single guy was born with weird asian-looking eyelids and this trait was passed on. This guy and his tribe fucked a lot.
From what I've read it evolved independently of asians. It is possible that this trait was very successful because snow reflects light so it was good to protect your eyes by making them into small slits. This is different to asians who developed slits for eyes to protect from dust.