By DNA, most people will have some descent from Abraham — he was 4000 years ago. That’s enough time for his genes to dissipate to some of the Chinese to some of the Irish and to some of the sub-saharan Africans. Perhaps even you, amorphous.
For the purpose of tracking down the lost tribes of Israel, I would assume one would attempt to retrieve the closest sample of DNA, prior to the branching, as possible. Perhaps the bones of Jacob, if they could be located, would provide the perfect sample if they are not too dried out. And then there may be other means of determining the gene pool. But yes, even I could be a decedent of one of the sons of Jacob, like millions of others.