Not one example

There was a paper that attempted to provide some genetic evidence for this, but it, and the author, were attacked, the paper unprecedentedly deleted, and the author shortly thereafter apparently smeared with false embezzlement charges. Make of that what you will.

He is a bit of a nut job when it comes to the Basque language, though, hilariously.

https://en.wikipedia.org/wiki/Antonio_Arnaiz-Villena https://www.theguardian.com/world/2001/nov/25/medicalscience.genetics https://www.bmj.com/content/324/7339/695.1

What makes it ok for your grandparents, great-grandparents et cetera, but not for these poor souls in the exact same situation? The same could be said for most places if you back far enough. People constantly trying to shut the door behind them, and it’s made worse by pure lies about work. 99.99•% of immigrants work hard af and pay taxes, unlike the top 0.1%