To me it seems certain belief systems help people to restrain bad traits and come to good traits. Other belief systems seem to aggravate already existing bad traits. But little comes close to the power that DNA has on people.
Reb Israel Salanter already noted the difficulty in one's correcting his own bad traits.
It seems pretty clear to me that when people think they are repenting, they are as a rule just reinforcing in themselves their own messed up ideas.It is clear like Rav Salanter said:One can have good traits without Musar. But one can not go from bad traits to good traits without Musar.
[Musar [ethical works from the Middle Ages] has a limited definition. Not everything people claim is Musar is actually Musar.
There are also however specific lessons to accept from certain tzadikim. The Gra revealed the importance of learning Torah. The aspect of learning in depth however really is a Litvak thing.
In any case if one would thing about the caste system idea the most likely place to look would be the descendants of Rav Yaakov Abuchatzaira. That is not from DNA, but rather some kind of אור מקיף divine light that seems to surround that family. Not that it is same thing as it used to be; still there is some aspect of the whole Bava Sali thing that I think is still there.
The descendants of Rav Abuchatzeira are mostly located in Israel.