Paul seemed to think his Hebrew ethnicity was worthless in the sight of God.
"Circumcised the eighth day, of the stock of Israel, of the tribe of Benjamin, an Hebrew of the Hebrews . . . But what things were gain to me, those I counted loss for Christ. Yea, doubtless, and I count all things but loss for the excellency of the knowledge of Christ, Jesus my Lord: for whom I have suffered the loss of all things, and do count them but dung, that I may win Christ." - Philippians 3:5-8.
To put it in modern terms, Paul's Benjaminite ethnicity plus $2.50 would get him a ride on the train in Chicago. And he knew it.
I have no doubt that many modern Jews have a significant helping of ancient Jewish DNA. So do many modern Palestinians. So what?