I've known for a while now that the Simpsons originally migrated to the United States from the lowlands of Scotland, probably through Ireland, about 1700. History books have described my Simpson ancestors as Scotch-Irish and I have many distant DNA cousins living in Scotland and Northern Ireland.
However, my obsessive personality and fascination with DNA has driven me to continue to dig deeper. So after even more testing I have unearthed that which I already knew. Yes, the Simpsons are very likely from Scotland. Shocker.
The Y-chromosome mutates every few generations. By analyzing the distribution of men with these mutations, we can tell when mutations occurred and very roughly where. Older mutations are easier to discover and analyze than new mutations so we can easily determine that half of European men descend from a common ancestor who lived on the steppes of central Asia about 40,000 years ago. However, mutations that happened a few thousand years ago are much harder to find and analyze, mostly because far fewer people have them.
So I now know that the Simpson men have a mutation at the Y8402 gene. This mutation likely originated in a man born more than 1,200 years ago, somewhere in northern England, North Ireland, or Scotland. This was long before there were surnames in the region so there were no Simpsons then but its positive proof that our distant paternal ancestors lived in that region long ago. It doesn't yet narrow it down whether this paternal line was Celtic, Saxon, or some other Viking race but we're getting closer.