I hear you-One of my friends is 100% Irish and tans beautifully, while I am at least 25% Italian and only burn...Go figure.
By now all our DNA is quite watered down and I don’t think it is really that possible to pinpoint the ancestry of First World nations at least. In my example, we had girls of identical ancestry having drastically different tanning ability.
I haven’t had my DNA tested. I can trace my ancestry back ten to fifteen generations so far my ancesters and those of my husband are hanging out around the North Sea.