Passage: Red hair is most commonly found at the northern and western fringes of Europe; it is centered around populations in the British Isles. Redheads today are commonly associated with the Celtic nations.In Ireland, the percentage of population with red hair is estimated to be at around 10%, making it the world's highest concentrated population of red heads. According to IrelandsDNA, 34.7% of the Irish population carry the allele for red hair, although this doesn't directly translate proportionally into births of red-haired children.Scotland also has a high percentage with around 6% of the population having red hair, with Edinburgh being the redhead capital of the world. The most redheaded region is the south-east of Scotland with Edinburgh as a red head hotspot. There, four-in-10 carry one of the three most common red hair genes. Scotland as whole has a higher percentage than Ireland, 36.5 per cent as against 34.7 according to a survey taken by BritainsDNA.England has a red hair prevalence of around 4%, with 28.5% of population having the allele; while in Wales 38% of Welsh people carry the red-haired allele. A 1956 study of hair colour among British Army recruits from Great Britain found higher levels of red hair in Wales and the Scottish border counties of England.

Question: Which part of the UK has the population with the highest incidence of red hair genes?
Wales