The dying ginger gene mapped across Europe.
NUI Maynooth Biology professor James McInerney writes:
This diagram shows the distribution of red hair in Europe…
Genomic data is likely to answer a few questions on this [the reasons cluster of red-haired people] – like whether Red hair was more widely distributed throughout Europe in the past and nowadays it is only found on the periphery because of a later take-over of Europe by people that didn’t have red hair or alternatively, Red Hair might have originated in those places where is is found now and it never had a wide distribution….
No word on brown haired men who have red beards then.