How does genetics tie into spirituality?

TEXT:

"For it is evident that our Lord sprang out of Juda; of which tribe Moses spake nothing concerning priesthood.
And it is yet far more evident: for that after the similitude of Melchisedec there ariseth another priest,
Who is made, not after the law of a carnal commandment, but after the power of an endless life.
For he testifieth, Thou art a priest for ever after the order of Melchisedec." (Heb. 7:14-17)

DISCUSSION:

1. "sprang out of Juda" of the lineage of David - Melchisedec was not even a Jew. What is going on here?

2, How does this support the relevance or lack thereof of genetics in regards to spirituality?

How does genetics tie into spirituality?