I would take serious issue with that. A story was done just within the last few days in which the dna of a line of women believed to be Amazon warriors from a period roughly 2500 years back - some 500 years before Christ, has been matched to the line of a single young girl living today. There is a way to tell. And it is DNA, among other things. There is plenty of historical factual and circumstantial evidence to bolster the claim. And this is not the only tribal group that has been located.
I don't believe they have identified anyone from the lost tribe of Israel through DNA?