What's interesting is how strong the selection pressure seems to be to have melanin content adjusted to match the local conditions for sunlight. In the western

What's interesting is how strong the selection pressure seems to be to have melanin content adjusted to match the local conditions for sunlight. In the western hemisphere, where humans have only lived for ~20,000 years, there was already notable variations in pigmentation developing prior to 1500AD. That would make sense if vitamin D production is very important to health.