R1b is becouse invaders from Asia (in this case R1b people) had sex-orgies with indogenous Basques (which were not R1b) and that is a result from paternal line of mixing.
They keep their language from the mother side (which were not Indo-European) :)
But father was of Asian origin. So R1a and R1b is the same branch. Asian origin people who didn't look European, like we have a lot of them today. (result of mixing with white people).

