A man was buried in a cave in northern Spain seven thousand years ago. When his genome was published in 2014 it broke the picture everyone had in their head: he carried the variant for blue eyes, alongside the variants for dark skin and dark hair. And he is one of the closest known relatives of the first people ever to walk into Britain and Ireland.

If you have blue eyes and your family came out of Scotland or Ireland, you have probably been told who brought them. The Vikings. The Celts. The Normans. Every one of those answers is wrong, and wrong by thousands of years.

Tonight: seven suspects, eliminated one by one.

7. The Vikings — Lindisfarne was 793; the colour was here millennia earlier
— there is no "blue eye gene": rs12913832, HERC2, OCA2, and why no human eye contains blue pigment
6. The Anglo-Saxons (and the Normans) — late, and in the wrong places
5. The Beaker people — 90% population replacement, and still only carriers (the Rathlin Island men, 2000 BC)
4. The first farmers — the twist: they made blue eyes RARER (Ballynahatty, and the Newgrange man whose parents were brother and sister)
3. The steppe — it changed European skin, language and milk, but not this
2. The Villabruna wave — 14,000 years ago, the people who carried the switch into western Europe
1. The Mesolithic hunter-gatherers — Cheddar Man, Loschbour, La Braña, Mount Sandel: it was already here

And the real question at the end: if farming pushed the frequency down, why are Scotland and Ireland among the blue-eyed capitals of the world?

What colour are your eyes, and which county or island did your family come from? Tell me in the comments.

🔎 TRACE YOUR SURNAME: https://dnaorigin.org
Your eyes go back ten thousand years. Your surname goes back about eight hundred — and that is the part you can actually trace. Type in your surname and it does the research for you: the region it began in, what it means, the clan or family, when it crossed the water, and the families who carried it before you. Or scan the QR code on screen.