The Old Testament has a question hanging over it: "Who will inherit the promises to Abraham?". Isaac is chosen over Ishmael, Jacob over Esau and (though in one sense all the sons of Jacob inherit) Judah is chosen over his brothers. Likewise Perez over Zerah and so on through the line of David.
There is a parallel theme of a 'remnant' surviving God's judgement on disobedient Israel, and the survival of Judah when Ephraim is destroyed is part of that theme. Though Judah is eventually sent into exile, it is the remnant of Judah that returns and Judah's line that ultimately leads to Jesus (though not through a human father).
In that light, what is the significance that the one disciple who betrays Jesus is named Judas (the Greek for Judah)? Is the intention to highlight that the old cycle of rebellion, judgement, 'repentance' and relenting has finally come to an end?