Map showing frequency of red hair across Europe. Five color-coded ranges: red (over 10%) concentrated in Ireland and Scotland, orange (5-9%) in parts of UK and northern Europe, brown (2-4%) in Scandinavia and Germany, darker brown (1-2%) in central Europe, and darkest brown (under 1%) in southern Europe. Shows clear north-south gradient with highest concentrations in Celtic regions.
Because the Vikings settled and formed The Russians around Ukraine, from where they spread and eventually formed Russia.
But what about that red head spot?
There must be some (maybe forgotten) wild story about it
I think that's Udmurtia. Udmurts are an Ugric minority people within Russia, and they've got a really high incidence of red hair
Somebody with red hair had a lot of children there right before the population suddenly grew. Or maybe was one of the survivors when it regrew after a national disaster. The founder effect, in other words.
Other people are talking about selection. The numbers are in, that accounts for maybe 5% of genetic change over the last 10,000 years. The rest is just chaos.
That's closer to Khazakhstan.