This article argues that the UK is just one big happy family. The British isles were populated by Iberians 8,000 or 9,000 years ago, and everyone throughout the isles– Irish, Welsh, Scottish and English is mainly descended from those post-Ice Age settlers from what is now Spain and Portugal. The Angles and Saxons who came more recently just intermarried with local folks and their haplotypes or DNA patterns are not distinctive by now.
Me, I am suspicious of this whole way of thinking. Are Britons and Irish really all that closer to Iberians than to other Europeans?
And, Homo sapiens sapiens is only about 100,000 years old, so why stop with the Iberians? Brian Sykes showed in The Seven Daughters of Eve that all Europeans’ mitochondrial DNA shows one of seven patterns associated with maternal ancestors who lived 16,000 to 25,000 years ago (and this was true of isolated ethnicities such as Basques as well as everyone else). The mix was not remarkably different anywhere in Europe. And even that result is artificial, since sometimes women only have sons and you lose the mitochondrial DNA thread. In fact, we’re all Africans, and have been so relatively recently in history.
The problem with DNA history is that it privileges certain minor parts of the genome and is open to manipulation for the purposes of identity politics.