This is also why the Rabbinical consensus until recently opposed any suggestion of building a Jewish state, and religious arguments for the Zionist movement only gained popular support as conditions in Europe grew exceedingly worse for Jews. For example sake, note that the First Zionist Congress of 1897 was originally to be held in Munich, but was moved to Basel under protest from the large Jewish communities in Germany.
As for the ancient ancestral claims, here is a report on a DNA study from the Hebrew University in Jerusalem:
http://bric.postech.ac.kr/science/97now/00_10now/001030a.html
So, again, the theological linages you two are discussing hold no weight in either side's claim to the land over the other.